# 配置

Kafka 使用 [**property file 格式**](http://en.wikipedia.org/wiki/.properties) 键值对进行配置。这些数值可以通过文件或者编程形式指定。

## [3.1 Broker 配置](#brokerconfigs) <a href="#brokerconfigs" id="brokerconfigs"></a>

核心的必要配置信息如下：

* `broker.id`
* `log.dirs`
* `zookeeper.connect`

Topic 级别的配置和默认值在[下面](http://kafka.apache.org/documentation.html#topic-config) 进行更深入的讨论。

| 名称                                            | 描述                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | 类型       | 默认值                                                                 | 有效值                          | 重要性    |
| --------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- | ------------------------------------------------------------------- | ---------------------------- | ------ |
| zookeeper.connect                             | Zookeeper 连接字符串 /ZK 地址                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | string   | null                                                                |                              | high   |
| advertised.host.name                          | <p>弃用：只有当'advertised.listeners'或者'listeners'没有设置时使用。使用'advertised.listeners'来取代。发布到 ZooKeeper 供客户端使用的的 Hostname。在 IaaS 环境中，这个配置可能与 broker 绑定的接口不同。如果这个值没有设置那么它将使用已配置的'host.name'，如果'host.name'也没有配置它将返回 java.net.InetAddress.getCanonicalHostName() 的值。<br>only used when 'advertised.listeners' or 'listeners' are not set. Use 'advertised.listeners' instead. Hostname to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, it will use the value for 'host.name' if configured. Otherwise it will use the value returned from java.net.InetAddress.getCanonicalHostName().</p> | string   | null                                                                |                              | high   |
| advertised.listeners                          | <p>发布到 ZooKeeper 供客户端使用的监听器（译者注：broker 监听的网络接口，例如 PLAINTEXT://192.168.71.31:9092 或者 security_protocol://host_name:port），如果与上面配置的'listeners'不同。在 Iaas 环境，这个值可能要和 broker 绑定的接口不同。假如没有设置将使用'listeners'的值。<br>Listeners to publish to ZooKeeper for clients to use, if different than the listeners above. In IaaS environments, this may need to be different from the interface to which the broker binds. If this is not set, the value for 'listeners' will be used.</p>                                                                                                                                                                                                                        | string   | null                                                                |                              | high   |
| advertised.port                               | <p>弃用：只有当'advertised.listeners'或者'listeners'没有配置的时候起效。使用 'advertised.listeners'代替。发布到 ZooKeeper 供客户端使用的端口。在 IaaS 环境中，这个端口后可能需要和 Broker 绑定的不同。如果没有配置将使用 broker 绑定的端口值。<br>DEPRECATED: only used when 'advertised.listeners' or 'listeners' are not set. Use 'advertised.listeners' instead. The port to publish to ZooKeeper for clients to use. In IaaS environments, this may need to be different from the port to which the broker binds. If this is not set, it will publish the same port that the broker binds to.</p>                                                                                                                                                                    | int      | null                                                                |                              | high   |
| auto.create.topics.enable                     | <p>允许在服务器上自动创建主题 (topic)<br>Enable auto creation of topic on the server</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | boolean  | true                                                                |                              | high   |
| auto.leader.rebalance.enable                  | <p>是否启动自动 leader 均衡，一个后台线程按周期检查然后按需触发 leader 重选<br>Enables auto leader balancing. A background thread checks and triggers leader balance if required at regular intervals</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | boolean  | true                                                                |                              | high   |
| background.threads                            | <p>后台处理任务使用的线程数<br>The number of threads to use for various background processing tasks</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | int      | 10                                                                  | \[1,...]                     | high   |
| **broker.id**                                 | <p>这个服务器上 broker 的 id。如果不设置，将生成一个唯一的 broker id。为了避免基于 Zookeeper 生成的 broker id 与用户配置的发生冲突，生成的 broker id 从 reserved.broker.max.id + 1 开始。<br>The broker id for this server. If unset, a unique broker id will be generated.To avoid conflicts between zookeeper generated broker id's and user configured broker id's, generated broker idsstart from reserved.broker.max.id + 1.</p>                                                                                                                                                                                                                                                                                                             | int      | -1                                                                  |                              | high   |
| compression.type                              | <p>为特定的 topic 指定最终的压缩类型。这个配置接受标准的压缩编码 ('gzip', 'snappy', 'lz4')。另外它接受'uncompressed'参数指明不进行压缩；同时'producer'值表示保留生产者指定的压缩类型<br>Specify the final compression type for a given topic. This configuration accepts the standard compression codecs ('gzip', 'snappy', 'lz4'). It additionally accepts 'uncompressed' which is equivalent to no compression; and 'producer' which means retain the original compression codec set by the producer.</p>                                                                                                                                                                                                                                                 | string   | producer                                                            |                              | high   |
| delete.topic.enable                           | <p>是否允许删除 topic。如果这个配置被关闭则通过 admin tool 删除 topic 将失效。<br>Enables delete topic. Delete topic through the admin tool will have no effect if this config is turned off</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | boolean  | false                                                               |                              | high   |
| host.name                                     | <p>弃用：只有当'listeners'没有配置的时候起效。如果这个配置被设置，它将仅仅绑定到这个地址，如果没有设置将绑定到所有的接口上。<br>DEPRECATED: only used when 'listeners' is not set. Use 'listeners' instead. hostname of broker. If this is set, it will only bind to this address. If this is not set, it will bind to all interfaces</p>                                                                                                                                                                                                                                                                                                                                                                                                              | string   | ""                                                                  |                              | high   |
| leader.imbalance.check.interval.seconds       | <p>控制器触发分区重分配检查的周期<br>The frequency with which the partition rebalance check is triggered by the controller</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | 300                                                                 |                              | high   |
| leader.imbalance.per.broker.percentage        | <p>每个 broker 上的 leader 不均衡比例。如果每个 broker 上的 leader 不均衡比例超过此数值控制器将触发一个 leader 均衡。这个数值按照百分比指定。（译者注：由于 Replication 机制 Partition 都有多个副本，这个副本列表 AR 第一个称为 Preferred Replica，Kafka 要保证 Preferred Replica 均匀分到 broker 上，因为对于某个 Partition 的读写操作都由这个副本完成。）<br>The ratio of leader imbalance allowed per broker. The controller would trigger a leader balance if it goes above this value per broker. The value is specified in percentage.</p>                                                                                                                                                                                                                                                           | int      | 10                                                                  |                              | high   |
| listeners                                     | <p>监听接口列表 - 一个逗号分隔的 URI 列表我们将使用指定的协议监听这些地址。指定 hostname 为 0.0.0.0 将绑定所有的接口。留空 hostname 将绑定到默认的接口。实例合法的监听接口列表为：PLAINTEXT://myhost:9092,TRACE://:9091 PLAINTEXT://0.0.0.0:9092, TRACE://localhost:9093<br>Listener List - Comma-separated list of URIs we will listen on and their protocols. Specify hostname as 0.0.0.0 to bind to all interfaces. Leave hostname empty to bind to default interface. Examples of legal listener lists: PLAINTEXT://myhost:9092,TRACE://:9091 PLAINTEXT://0.0.0.0:9092, TRACE://localhost:9093</p>                                                                                                                                                               | string   | null                                                                |                              | high   |
| log.dir                                       | <p>日志文件存储的位置（log.dirs 配置的补充）<br>The directory in which the log data is kept (supplemental for log.dirs property)</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | string   | /tmp/kafka-logs                                                     |                              | high   |
| log.dirs                                      | <p>日志文件存储的位置列表，如果没有设置将使用 log.dir<br>The directories in which the log data is kept. If not set, the value in log.dir is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | string   | null                                                                |                              | high   |
| log.flush.interval.messages                   | <p>在消息被刷新到磁盘之前允许在单个日志分区上堆积的消息的数量<br>The number of messages accumulated on a log partition before messages are flushed to disk</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | long     | 9223372036854775807                                                 | \[1,...]                     | high   |
| log.flush.interval.ms                         | <p>任意 topic 上的消息在刷新到硬盘之前允许其保存在内存中的最大 ms 数。如果没有设置则使用 log.flush.scheduler.interval.ms 配置<br>The maximum time in ms that a message in any topic is kept in memory before flushed to disk. If not set, the value in log.flush.scheduler.interval.ms is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                                     | long     | null                                                                |                              | high   |
| log.flush.offset.checkpoint.interval.ms       | <p>更新最后一次 flush 的持久化消息为日志恢复点的频率<br>The frequency with which we update the persistent record of the last flush which acts as the log recovery point</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | int      | 60000                                                               | \[0,...]                     | high   |
| log.flush.scheduler.interval.ms               | <p>刷新检查是否有 log 需要被刷新到硬盘的频率用 ms 表示<br>The frequency in ms that the log flusher checks whether any log needs to be flushed to disk</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | long     | 9223372036854775807                                                 |                              | high   |
| log.retention.bytes                           | <p>保留的日志最大的大小<br>The maximum size of the log before deleting it</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | long     | -1                                                                  |                              | high   |
| log.retention.hours                           | <p>在删除之前日志文件保存的最长时间（小时计）, 相比 log.retention.ms 第三优先<br>The number of hours to keep a log file before deleting it (in hours), tertiary to log.retention.ms property</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | int      | 168                                                                 |                              | high   |
| log.retention.minutes                         | <p>在删除之前日志文件保存的最长时间（分钟计），相比 log.retention.ms 第二优先。如果没有设置 log.retention.hours 中的值将被使用<br>The number of minutes to keep a log file before deleting it (in minutes), secondary to log.retention.ms property. If not set, the value in log.retention.hours is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                              | int      | null                                                                |                              | high   |
| log.retention.ms                              | <p>在删除之前日志文件保存的最长微秒数（微秒计）, 如果没有设置 log.retention.minutes 中的值将被使用<br>The number of milliseconds to keep a log file before deleting it (in milliseconds), If not set, the value in log.retention.minutes is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | long     | null                                                                |                              | high   |
| log.roll.hours                                | <p>切分新日志段的最长时间间隔（小时计），相比 log.roll.ms 第二优先<br>The maximum time before a new log segment is rolled out (in hours), secondary to log.roll.ms property</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | int      | 168                                                                 | \[1,...]                     | high   |
| log.roll.jitter.hours                         | <p>切分新日志段时间的随机偏移量（小时计），相比 log.roll.jitter.ms 第二优先级（译者注：添加时间随机偏移量是为了防止惊群问题。）<br>The maximum jitter to subtract from logRollTimeMillis (in hours), secondary to log.roll.jitter.ms property</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | int      | 0                                                                   | \[0,...]                     | high   |
| log.roll.jitter.ms                            | <p>切分新日志段时间的随机偏移量（毫秒计），未设置则使用 log.roll.jitter.hours<br>The maximum jitter to subtract from logRollTimeMillis (in milliseconds). If not set, the value in log.roll.jitter.hours is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | long     | null                                                                |                              | high   |
| log.roll.ms                                   | <p>切分新日志段的最长时间间隔（毫秒计），如果不设置则使用 log.roll.hours<br>The maximum time before a new log segment is rolled out (in milliseconds). If not set, the value in log.roll.hours is used</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | null                                                                |                              | high   |
| log.segment.bytes                             | <p>单个日志文件最大大小<br>The maximum size of a single log file</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 1073741824                                                          | \[14,...]                    | high   |
| log.segment.delete.delay.ms                   | <p>日志分段从文件系统删除前的延迟<br>The amount of time to wait before deleting a file from the filesystem</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | 60000                                                               | \[0,...]                     | high   |
| message.max.bytes                             | <p>服务器可接受的最大消息的大小<br>The maximum size of message that the server can receive</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | int      | 1000012                                                             | \[0,...]                     | high   |
| min.insync.replicas                           | <p>定义 ACK 生产者请求前 ISR 中最小的副本数<br>define the minimum number of replicas in ISR needed to satisfy a produce request with acks=all (or -1)</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 1                                                                   | \[1,...]                     | high   |
| num.io.threads                                | <p>服务器为网络请求服务的 IO 线程数<br>The number of io threads that the server uses for carrying out network requests</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 8                                                                   | \[1,...]                     | high   |
| num.network.threads                           | <p>服务器处理网络请求的网络线程数<br>the number of network threads that the server uses for handling network requests</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 3                                                                   | \[1,...]                     | high   |
| num.recovery.threads.per.data.dir             | <p>每个日志文件夹在启停时日志恢复使用的线程数（译者注：RAID 可以增大数值）<br>The number of threads per data directory to be used for log recovery at startup and flushing at shutdown</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 1                                                                   | \[1,...]                     | high   |
| num.replica.fetchers                          | <p>从源节点抓取副本消息的抓取线程数。这个值越高从节点的 IO 同步性越好<br>Number of fetcher threads used to replicate messages from a source broker. Increasing this value can increase the degree of I/O parallelism in the follower broker.</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 1                                                                   |                              | high   |
| offset.metadata.max.bytes                     | <p>offset 队列中元数据的最大大小（译者注： 之前版本，Kafka 其实存在一个比较大的隐患，就是利用 Zookeeper 来存储记录每个消费者 / 组的消费进度。从 0.10.1.1 版本已默认将消费的 offset 迁入到了 Kafka 一个名为 <code>__consumer_offsets</code> 的 Topic 中。这个 Topic 使用 group、topic、partition 三元组维护一个 offset 信息。）<br>The maximum size for a metadata entry associated with an offset commit</p>                                                                                                                                                                                                                                                                                                                                                                                 | int      | 4096                                                                |                              | high   |
| offsets.commit.required.acks                  | <p>offset 队列 commit 时需要的 ack 数量。一般情况下默认值 -1 不应该被修改（译者注： 因为这部分消息是非常重要，以至于是不能容忍丢数据的，生产者要等到所有的 ISR 都收到消息后才会得到 ack。数据安全性好自然其速度会有所影响。）<br>The required acks before the commit can be accepted. In general, the default (-1) should not be overridden</p>                                                                                                                                                                                                                                                                                                                                                                                                                                             | short    | -1                                                                  |                              | high   |
| offsets.commit.timeout.ms                     | <p>offset 队列接受 commit 的超时时间。这个设置与生产者请求超时时间相似<br>Offset commit will be delayed until all replicas for the offsets topic receive the commit or this timeout is reached. This is similar to the producer request timeout.</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 5000                                                                | \[1,...]                     | high   |
| offsets.load.buffer.size                      | <p>从 offset 日志段读取信息到缓存的批量加载大小<br>Batch size for reading from the offsets segments when loading offsets into the cache.</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 5242880                                                             | \[1,...]                     | high   |
| offsets.retention.check.interval.ms           | <p>检查旧的偏移量的频率，单位是毫秒<br>Frequency at which to check for stale offsets</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | long     | 600000                                                              | \[1,...]                     | high   |
| offsets.retention.minutes                     | <p>偏移量主题的日志保留窗口，单位是分钟<br>Log retention window in minutes for offsets topic</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | int      | 1440                                                                | \[1,...]                     | high   |
| offsets.topic.compression.codec               | <p>offsets topic 的压缩编码，压缩编码可以用于原子化提交<br>Compression codec for the offsets topic - compression may be used to achieve "atomic" commits</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 0                                                                   |                              | high   |
| offsets.topic.num.partitions                  | <p>offset topic 的分区数量（在部署后不应该再修改）<br>The number of partitions for the offset commit topic (should not change after deployment)</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | int      | 50                                                                  | \[1,...]                     | high   |
| offsets.topic.replication.factor              | <p>offsets topic 的复制因子（设置高一些要保证可用性）。为了保证 offsets topic 的复制因子有效，在 offsets topic 处理第一个请求的时候，存活的节点数必须大于或者等于复制因子。否则 offsets topic 创建将会失败或者使用两者之间的最小值（存活节点数、配置的复制因子）<br>The replication factor for the offsets topic (set higher to ensure availability). To ensure that the effective replication factor of the offsets topic is the configured value, the number of alive brokers has to be at least the replication factor at the time of the first request for the offsets topic. If not, either the offsets topic creation will fail or it will get a replication factor of min(alive brokers, configured replication factor)</p>                                                               | short    | 3                                                                   | \[1,...]                     | high   |
| offsets.topic.segment.bytes                   | <p>offsets topic 的段大小应该设置的相对较小来保证快速的日志压缩和缓存加载<br>The offsets topic segment bytes should be kept relatively small in order to facilitate faster log compaction and cache loads</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 104857600                                                           | \[1,...]                     | high   |
| port                                          | <p>已过时：仅仅当”listeners“没有被配置时有效。使用”listeners“来取代此配置。监听和接受连接的端口<br>DEPRECATED: only used when 'listeners' is not set. Use 'listeners' instead. the port to listen and accept connections on</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 9092                                                                |                              | high   |
| queued.max.requests                           | <p>在阻塞网络线程之前允许的请求队列最大的长度<br>The number of queued requests allowed before blocking the network threads</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 500                                                                 | \[1,...]                     | high   |
| quota.consumer.default                        | <p>按照 clientId/consumer group 定义的任何消费者每秒允许拉取的限额（byte）<br>Any consumer distinguished by clientId/consumer group will get throttled if it fetches more bytes than this value per-second</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | long     | 9223372036854775807                                                 | \[1,...]                     | high   |
| quota.producer.default                        | <p>按照 clientId 定义的生产者每秒允许生产的限额（byte）<br>Any producer distinguished by clientId will get throttled if it produces more bytes than this value per-second</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | long     | 9223372036854775807                                                 | \[1,...]                     | high   |
| replica.fetch.max.bytes                       | <p>允许复制者拉取消息集的最大小小<br>The number of bytes of messages to attempt to fetch</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | int      | 1048576                                                             |                              | high   |
| replica.fetch.min.bytes                       | <p>复制者拉取消息响应最小的大小。如果不足此大小响应延迟到 replicaMaxWaitTimeMs 返回（译者注：防止小包问题）<br>Minimum bytes expected for each fetch response. If not enough bytes, wait up to replicaMaxWaitTimeMs</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | int      | 1                                                                   |                              | high   |
| replica.fetch.wait.max.ms                     | <p>复制者拉取消息响应最大的等待时间。这个设置必须小于 replica.lag.time.max.ms 来防止低吞吐量 Topic 出现经常性的 ISR 丢失<br>max wait time for each fetcher request issued by follower replicas. This value should always be less than the replica.lag.time.max.ms at all times to prevent frequent shrinking of ISR for low throughput topics</p>                                                                                                                                                                                                                                                                                                                                                                                       | int      | 500                                                                 |                              | high   |
| replica.high.watermark.checkpoint.interval.ms | <p>replica 将最高水位进行 flush 到磁盘的时间间隔<br>The frequency with which the high watermark is saved out to disk</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | long     | 5000                                                                |                              | high   |
| replica.lag.time.max.ms                       | <p>如果在这个时间点前复制者没有发送任何拉取请求或者复制者没有消费到 Leader 日志最终偏移量，Leader 将会将此复制者从 ISR 中移除<br>If a follower hasn't sent any fetch requests or hasn't consumed up to the leaders log end offset for at least this time, the leader will remove the follower from isr</p>                                                                                                                                                                                                                                                                                                                                                                                                                                         | long     | 10000                                                               |                              | high   |
| replica.socket.receive.buffer.bytes           | <p>网络请求的 Socket 接收缓存<br>The socket receive buffer for network requests</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 65536                                                               |                              | high   |
| replica.socket.timeout.ms                     | <p>网络请求的 Socket 超时时间。这个值应该至少大于 replica.fetch.wait.max.ms<br>The socket timeout for network requests. Its value should be at least replica.fetch.wait.max.ms</p>                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 30000                                                               |                              | high   |
| request.timeout.ms                            | <p>这个配置控制着客户端等待请求响应的最大时间。如果在这个时间之后依旧没有收到响应，客户端将按需重发或者当禁用重试时直接认为请求失败<br>The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.</p>                                                                                                                                                                                                                                                                                                                                                   | int      | 30000                                                               |                              | high   |
| socket.receive.buffer.bytes                   | The SO\_RCVBUF buffer of the socket sever sockets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 102400                                                              |                              | high   |
| socket.request.max.bytes                      | The maximum number of bytes in a socket request                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 104857600                                                           | \[1,...]                     | high   |
| socket.send.buffer.bytes                      | The SO\_SNDBUF buffer of the socket sever sockets                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 102400                                                              |                              | high   |
| unclean.leader.election.enable                | Indicates whether to enable replicas not in the ISR set to be elected as leader as a last resort, even though doing so may result in data loss                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | boolean  | true                                                                |                              | high   |
| zookeeper.connection.timeout.ms               | The max time that the client waits to establish a connection to zookeeper. If not set, the value in zookeeper.session.timeout.ms is used                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | int      | null                                                                |                              | high   |
| zookeeper.session.timeout.ms                  | Zookeeper session timeout                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 6000                                                                |                              | high   |
| zookeeper.set.acl                             | Set client to use secure ACLs                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | boolean  | false                                                               |                              | high   |
| broker.id.generation.enable                   | Enable automatic broker id generation on the server? When enabled the value configured for reserved.broker.max.id should be reviewed.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | boolean  | true                                                                |                              | medium |
| broker.rack                                   | Rack of the broker. This will be used in rack aware replication assignment for fault tolerance. Examples: 'RACK1', 'us-east-1d'                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | string   | null                                                                |                              | medium |
| connections.max.idle.ms                       | Idle connections timeout: the server socket processor threads close the connections that idle more than this                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | long     | 600000                                                              |                              | medium |
| controlled.shutdown.enable                    | Enable controlled shutdown of the server                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | boolean  | true                                                                |                              | medium |
| controlled.shutdown.max.retries               | Controlled shutdown can fail for multiple reasons. This determines the number of retries when such failure happens                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | int      | 3                                                                   |                              | medium |
| controlled.shutdown.retry.backoff.ms          | Before each retry, the system needs time to recover from the state that caused the previous failure (Controller fail over, replica lag etc). This config determines the amount of time to wait before retrying.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | 5000                                                                |                              | medium |
| controller.socket.timeout.ms                  | The socket timeout for controller-to-broker channels                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | int      | 30000                                                               |                              | medium |
| default.replication.factor                    | default replication factors for automatically created topics                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 1                                                                   |                              | medium |
| fetch.purgatory.purge.interval.requests       | The purge interval (in number of requests) of the fetch request purgatory                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 1000                                                                |                              | medium |
| group.max.session.timeout.ms                  | The maximum allowed session timeout for registered consumers. Longer timeouts give consumers more time to process messages in between heartbeats at the cost of a longer time to detect failures.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 300000                                                              |                              | medium |
| group.min.session.timeout.ms                  | The minimum allowed session timeout for registered consumers. Shorter timeouts leader to quicker failure detection at the cost of more frequent consumer heartbeating, which can overwhelm broker resources.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 6000                                                                |                              | medium |
| inter.broker.protocol.version                 | Specify which version of the inter-broker protocol will be used. This is typically bumped after all brokers were upgraded to a new version. Example of some valid values are: 0.8.0, 0.8.1, 0.8.1.1, 0.8.2, 0.8.2.0, 0.8.2.1, 0.9.0.0, 0.9.0.1 Check ApiVersion for the full list.                                                                                                                                                                                                                                                                                                                                                                                                              | string   | 0.10.0-IV1                                                          |                              | medium |
| log.cleaner.backoff.ms                        | The amount of time to sleep when there are no logs to clean                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | long     | 15000                                                               | \[0,...]                     | medium |
| log.cleaner.dedupe.buffer.size                | The total memory used for log deduplication across all cleaner threads                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | long     | 134217728                                                           |                              | medium |
| log.cleaner.delete.retention.ms               | How long are delete records retained?                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | long     | 86400000                                                            |                              | medium |
| log.cleaner.enable                            | Enable the log cleaner process to run on the server? Should be enabled if using any topics with a cleanup.policy=compact including the internal offsets topic. If disabled those topics will not be compacted and continually grow in size.                                                                                                                                                                                                                                                                                                                                                                                                                                                     | boolean  | true                                                                |                              | medium |
| log.cleaner.io.buffer.load.factor             | Log cleaner dedupe buffer load factor. The percentage full the dedupe buffer can become. A higher value will allow more log to be cleaned at once but will lead to more hash collisions                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | double   | 0.9                                                                 |                              | medium |
| log.cleaner.io.buffer.size                    | The total memory used for log cleaner I/O buffers across all cleaner threads                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 524288                                                              | \[0,...]                     | medium |
| log.cleaner.io.max.bytes.per.second           | The log cleaner will be throttled so that the sum of its read and write i/o will be less than this value on average                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | double   | 1.7976931348623157E308                                              |                              | medium |
| log.cleaner.min.cleanable.ratio               | The minimum ratio of dirty log to total log for a log to eligible for cleaning                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | double   | 0.5                                                                 |                              | medium |
| log.cleaner.threads                           | The number of background threads to use for log cleaning                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | int      | 1                                                                   | \[0,...]                     | medium |
| log.cleanup.policy                            | The default cleanup policy for segments beyond the retention window, must be either "delete" or "compact"                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | delete                                                              | \[compact, delete]           | medium |
| log.index.interval.bytes                      | The interval with which we add an entry to the offset index                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | int      | 4096                                                                | \[0,...]                     | medium |
| log.index.size.max.bytes                      | The maximum size in bytes of the offset index                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | int      | 10485760                                                            | \[4,...]                     | medium |
| log.message.format.version                    | Specify the message format version the broker will use to append messages to the logs. The value should be a valid ApiVersion. Some examples are: 0.8.2, 0.9.0.0, 0.10.0, check ApiVersion for more details. By setting a particular message format version, the user is certifying that all the existing messages on disk are smaller or equal than the specified version. Setting this value incorrectly will cause consumers with older versions to break as they will receive messages with a format that they don't understand.                                                                                                                                                            | string   | 0.10.0-IV1                                                          |                              | medium |
| log.message.timestamp.difference.max.ms       | The maximum difference allowed between the timestamp when a broker receives a message and the timestamp specified in the message. If message.timestamp.type=CreateTime, a message will be rejected if the difference in timestamp exceeds this threshold. This configuration is ignored if message.timestamp.type=LogAppendTime.                                                                                                                                                                                                                                                                                                                                                                | long     | 9223372036854775807                                                 | \[0,...]                     | medium |
| log.message.timestamp.type                    | Define whether the timestamp in the message is message create time or log append time. The value should be either 'CreateTime' or 'LogAppendTime'                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | string   | CreateTime                                                          | \[CreateTime, LogAppendTime] | medium |
| log.preallocate                               | Should pre allocate file when create new segment? If you are using Kafka on Windows, you probably need to set it to true.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | boolean  | false                                                               |                              | medium |
| log.retention.check.interval.ms               | The frequency in milliseconds that the log cleaner checks whether any log is eligible for deletion                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | long     | 300000                                                              | \[1,...]                     | medium |
| max.connections.per.ip                        | The maximum number of connections we allow from each ip address                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 2147483647                                                          | \[1,...]                     | medium |
| max.connections.per.ip.overrides              | Per-ip or hostname overrides to the default maximum number of connections                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | ""                                                                  |                              | medium |
| num.partitions                                | The default number of log partitions per topic                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | int      | 1                                                                   | \[1,...]                     | medium |
| principal.builder.class                       | The fully qualified name of a class that implements the PrincipalBuilder interface, which is currently used to build the Principal for connections with the SSL SecurityProtocol.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | class    | class org.apache.kafka.common.security.auth.DefaultPrincipalBuilder |                              | medium |
| producer.purgatory.purge.interval.requests    | The purge interval (in number of requests) of the producer request purgatory                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 1000                                                                |                              | medium |
| replica.fetch.backoff.ms                      | The amount of time to sleep when fetch partition error occurs.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | int      | 1000                                                                | \[0,...]                     | medium |
| reserved.broker.max.id                        | Max number that can be used for a broker.id                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | int      | 1000                                                                | \[0,...]                     | medium |
| sasl.enabled.mechanisms                       | The list of SASL mechanisms enabled in the Kafka server. The list may contain any mechanism for which a security provider is available. Only GSSAPI is enabled by default.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | list     | \[GSSAPI]                                                           |                              | medium |
| sasl.kerberos.kinit.cmd                       | Kerberos kinit command path.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | string   | /usr/bin/kinit                                                      |                              | medium |
| sasl.kerberos.min.time.before.relogin         | Login thread sleep time between refresh attempts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | long     | 60000                                                               |                              | medium |
| sasl.kerberos.principal.to.local.rules        | A list of rules for mapping from principal names to short names (typically operating system usernames). The rules are evaluated in order and the first rule that matches a principal name is used to map it to a short name. Any later rules in the list are ignored. By default, principal names of the form {username}/{hostname}@{REALM} are mapped to {username}. For more details on the format please see [**security authorization and acls**](http://kafka.apache.org/documentation.html#security_authz).                                                                                                                                                                               | list     | \[DEFAULT]                                                          |                              | medium |
| sasl.kerberos.service.name                    | The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | string   | null                                                                |                              | medium |
| sasl.kerberos.ticket.renew.jitter             | Percentage of random jitter added to the renewal time.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | double   | 0.05                                                                |                              | medium |
| sasl.kerberos.ticket.renew.window.factor      | Login thread will sleep until the specified window factor of time from last refresh to ticket's expiry has been reached, at which time it will try to renew the ticket.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | double   | 0.8                                                                 |                              | medium |
| sasl.mechanism.inter.broker.protocol          | SASL mechanism used for inter-broker communication. Default is GSSAPI.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | string   | GSSAPI                                                              |                              | medium |
| security.inter.broker.protocol                | Security protocol used to communicate between brokers. Valid values are: PLAINTEXT, SSL, SASL\_PLAINTEXT, SASL\_SSL.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | string   | PLAINTEXT                                                           |                              | medium |
| ssl.cipher.suites                             | A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol.By default all the available cipher suites are supported.                                                                                                                                                                                                                                                                                                                                                                                                                 | list     | null                                                                |                              | medium |
| ssl.client.auth                               | Configures kafka broker to request client authentication. The following settings are common:`ssl.client.auth=required` If set to required client authentication is required.`ssl.client.auth=requested` This means client authentication is optional. unlike requested , if this option is set client can choose not to provide authentication information about itself`ssl.client.auth=none` This means client authentication is not needed.                                                                                                                                                                                                                                                   | string   | none                                                                | \[required, requested, none] | medium |
| ssl.enabled.protocols                         | The list of protocols enabled for SSL connections.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | list     | \[TLSv1.2, TLSv1.1, TLSv1]                                          |                              | medium |
| ssl.key.password                              | The password of the private key in the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | password | null                                                                |                              | medium |
| ssl.keymanager.algorithm                      | The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | string   | SunX509                                                             |                              | medium |
| ssl.keystore.location                         | The location of the key store file. This is optional for client and can be used for two-way authentication for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | string   | null                                                                |                              | medium |
| ssl.keystore.password                         | The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | password | null                                                                |                              | medium |
| ssl.keystore.type                             | The file format of the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | string   | JKS                                                                 |                              | medium |
| ssl.protocol                                  | The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.                                                                                                                                                                                                                                                                                                                                                                                                  | string   | TLS                                                                 |                              | medium |
| ssl.provider                                  | The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | string   | null                                                                |                              | medium |
| ssl.trustmanager.algorithm                    | The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | string   | PKIX                                                                |                              | medium |
| ssl.truststore.location                       | The location of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | null                                                                |                              | medium |
| ssl.truststore.password                       | The password for the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | password | null                                                                |                              | medium |
| ssl.truststore.type                           | The file format of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | string   | JKS                                                                 |                              | medium |
| authorizer.class.name                         | The authorizer class that should be used for authorization                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | string   | ""                                                                  |                              | low    |
| metric.reporters                              | A list of classes to use as metrics reporters. Implementing the `MetricReporter`interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.                                                                                                                                                                                                                                                                                                                                                                                                                                                               | list     | \[]                                                                 |                              | low    |
| metrics.num.samples                           | The number of samples maintained to compute metrics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | int      | 2                                                                   | \[1,...]                     | low    |
| metrics.sample.window.ms                      | The window of time a metrics sample is computed over.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | long     | 30000                                                               | \[1,...]                     | low    |
| quota.window.num                              | The number of samples to retain in memory                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 11                                                                  | \[1,...]                     | low    |
| quota.window.size.seconds                     | The time span of each sample                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 1                                                                   | \[1,...]                     | low    |
| ssl.endpoint.identification.algorithm         | The endpoint identification algorithm to validate server hostname using server certificate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | string   | null                                                                |                              | low    |
| zookeeper.sync.time.ms                        | How far a ZK follower can be behind a ZK leader                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 2000                                                                |                              | low    |

更多关于 broker 的配置信息可以在 scala 类 `kafka.server.KafkaConfig` 中找到。

[**Topic 级别配置**](http://kafka.apache.org/documentation.html#topic-config) 与 Topic 相关的配置既包含服务器默认值，也包含可选的每个 Topic 覆盖值。如果没有给出 Topic 单独的配置，那么服务器全局配置就会被使用。Topic 的配置可以在创建时通过一个或者多个 `--config` 选项来提供。本示例使用自定义的最大消息大小和刷新率创建一个名为 _my-topic_ 的 topic:

```
 > bin/kafka-topics.sh --zookeeper localhost:2181 --create --topic my-topic --partitions 1
        --replication-factor 1 --config max.message.bytes=64000 --config flush.messages=1
```

也可以在使用 `alter configs` 命令稍后更改或设置覆盖值。本示例重置 _my-topic_ 的最大消息的大小：

```
 > bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic my-topic
    --config max.message.bytes=128000
```

移除一个设置可以通过如下方法：

```
 > bin/kafka-topics.sh --zookeeper localhost:2181 --alter --topic my-topic
    --delete-config max.message.bytes
```

下面是 Topic 级别配置，服务器默认属性列是该属性的默认配置，修改该属性的服务器级别设置可以用来改变 Topic 的属性。

| 名称                        | 默认值                 | 服务器默认属性                         | 描述                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| ------------------------- | ------------------- | ------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| cleanup.policy            | delete              | log.cleanup.policy              | A string that is either "delete" or "compact". This string designates the retention policy to use on old log segments. The default policy ("delete") will discard old segments when their retention time or size limit has been reached. The "compact" setting will enable [**log compaction**](http://kafka.apache.org/documentation.html#compaction) on the topic.                                                                                                                                                                                                                                                                                                     |
| delete.retention.ms       | 86400000 (24 hours) | log.cleaner.delete.retention.ms | The amount of time to retain delete tombstone markers for [**log compacted**](http://kafka.apache.org/documentation.html#compaction) topics. This setting also gives a bound on the time in which a consumer must complete a read if they begin from offset 0 to ensure that they get a valid snapshot of the final stage (otherwise delete tombstones may be collected before they complete their scan).                                                                                                                                                                                                                                                                |
| flush.messages            | None                | log.flush.interval.messages     | This setting allows specifying an interval at which we will force an fsync of data written to the log. For example if this was set to 1 we would fsync after every message; if it were 5 we would fsync after every five messages. In general we recommend you not set this and use replication for durability and allow the operating system's background flush capabilities as it is more efficient. This setting can be overridden on a per-topic basis (see [**the per-topic configuration section**](http://kafka.apache.org/documentation.html#topic-config)).                                                                                                     |
| flush.ms                  | None                | log.flush.interval.ms           | This setting allows specifying a time interval at which we will force an fsync of data written to the log. For example if this was set to 1000 we would fsync after 1000 ms had passed. In general we recommend you not set this and use replication for durability and allow the operating system's background flush capabilities as it is more efficient.                                                                                                                                                                                                                                                                                                              |
| index.interval.bytes      | 4096                | log.index.interval.bytes        | This setting controls how frequently Kafka adds an index entry to it's offset index. The default setting ensures that we index a message roughly every 4096 bytes. More indexing allows reads to jump closer to the exact position in the log but makes the index larger. You probably don't need to change this.                                                                                                                                                                                                                                                                                                                                                        |
| max.message.bytes         | 1,000,000           | message.max.bytes               | This is largest message size Kafka will allow to be appended to this topic. Note that if you increase this size you must also increase your consumer's fetch size so they can fetch messages this large.                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| min.cleanable.dirty.ratio | 0.5                 | log.cleaner.min.cleanable.ratio | This configuration controls how frequently the log compactor will attempt to clean the log (assuming [**log compaction**](http://kafka.apache.org/documentation.html#compaction) is enabled). By default we will avoid cleaning a log where more than 50% of the log has been compacted. This ratio bounds the maximum space wasted in the log by duplicates (at 50% at most 50% of the log could be duplicates). A higher ratio will mean fewer, more efficient cleanings but will mean more wasted space in the log.                                                                                                                                                   |
| min.insync.replicas       | 1                   | min.insync.replicas             | When a producer sets acks to "all", min.insync.replicas specifies the minimum number of replicas that must acknowledge a write for the write to be considered successful. If this minimum cannot be met, then the producer will raise an exception (either NotEnoughReplicas or NotEnoughReplicasAfterAppend). When used together, min.insync.replicas and acks allow you to enforce greater durability guarantees. A typical scenario would be to create a topic with a replication factor of 3, set min.insync.replicas to 2, and produce with acks of "all". This will ensure that the producer raises an exception if a majority of replicas do not receive a write. |
| retention.bytes           | None                | log.retention.bytes             | This configuration controls the maximum size a log can grow to before we will discard old log segments to free up space if we are using the "delete" retention policy. By default there is no size limit only a time limit.                                                                                                                                                                                                                                                                                                                                                                                                                                              |
| retention.ms              | 7 days              | log.retention.minutes           | This configuration controls the maximum time we will retain a log before we will discard old log segments to free up space if we are using the "delete" retention policy. This represents an SLA on how soon consumers must read their data.                                                                                                                                                                                                                                                                                                                                                                                                                             |
| segment.bytes             | 1 GB                | log.segment.bytes               | This configuration controls the segment file size for the log. Retention and cleaning is always done a file at a time so a larger segment size means fewer files but less granular control over retention.                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| segment.index.bytes       | 10 MB               | log.index.size.max.bytes        | This configuration controls the size of the index that maps offsets to file positions. We preallocate this index file and shrink it only after log rolls. You generally should not need to change this setting.                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
| segment.ms                | 7 days              | log.roll.hours                  | This configuration controls the period of time after which Kafka will force the log to roll even if the segment file isn't full to ensure that retention can delete or compact old data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| segment.jitter.ms         | 0                   | log.roll.jitter.{ms,hours}      | The maximum jitter to subtract from logRollTimeMillis.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |

## [3.2 Producer 配置](#producerconfigs) <a href="#producerconfigs" id="producerconfigs"></a>

下面是 Java 生产者的配置：

| 名称                                       | 描述                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | 类型       | 默认值                                                                  | 有效值                 | 重要性    |
| ---------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- | -------------------------------------------------------------------- | ------------------- | ------ |
| bootstrap.servers                        | A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form`host1:port1,host2:port2,...`. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | list     |                                                                      |                     | high   |
| key.serializer                           | Serializer class for key that implements the`Serializer` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | class    |                                                                      |                     | high   |
| value.serializer                         | Serializer class for value that implements the`Serializer` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | class    |                                                                      |                     | high   |
| acks                                     | The number of acknowledgments the producer requires the leader to have received before considering a request complete. This controls the durability of records that are sent. The following settings are common:`acks=0` If set to zero then the producer will not wait for any acknowledgment from the server at all. The record will be immediately added to the socket buffer and considered sent. No guarantee can be made that the server has received the record in this case, and the`retries` configuration will not take effect (as the client won't generally know of any failures). The offset given back for each record will always be set to -1.`acks=1` This will mean the leader will write the record to its local log but will respond without awaiting full acknowledgement from all followers. In this case should the leader fail immediately after acknowledging the record but before the followers have replicated it then the record will be lost.`acks=all` This means the leader will wait for the full set of in-sync replicas to acknowledge the record. This guarantees that the record will not be lost as long as at least one in-sync replica remains alive. This is the strongest available guarantee. | string   | 1                                                                    | \[all, -1, 0, 1]    | high   |
| buffer.memory                            | The total bytes of memory the producer can use to buffer records waiting to be sent to the server. If records are sent faster than they can be delivered to the server the producer will block for`max.block.ms` after which it will throw an exception.This setting should correspond roughly to the total memory the producer will use, but is not a hard bound since not all memory the producer uses is used for buffering. Some additional memory will be used for compression (if compression is enabled) as well as for maintaining in-flight requests.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | long     | 33554432                                                             | \[0,...]            | high   |
| compression.type                         | The compression type for all data generated by the producer. The default is none (i.e. no compression). Valid values are `none`, `gzip`, `snappy`, or `lz4`. Compression is of full batches of data, so the efficacy of batching will also impact the compression ratio (more batching means better compression).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | string   | none                                                                 |                     | high   |
| retries                                  | Setting a value greater than zero will cause the client to resend any record whose send fails with a potentially transient error. Note that this retry is no different than if the client resent the record upon receiving the error. Allowing retries without setting`max.in.flight.requests.per.connection`to 1 will potentially change the ordering of records because if two batches are sent to a single partition, and the first fails and is retried but the second succeeds, then the records in the second batch may appear first.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | int      | 0                                                                    | \[0,...,2147483647] | high   |
| ssl.key.password                         | The password of the private key in the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | password | null                                                                 |                     | high   |
| ssl.keystore.location                    | The location of the key store file. This is optional for client and can be used for two-way authentication for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | string   | null                                                                 |                     | high   |
| ssl.keystore.password                    | The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | password | null                                                                 |                     | high   |
| ssl.truststore.location                  | The location of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | string   | null                                                                 |                     | high   |
| ssl.truststore.password                  | The password for the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | password | null                                                                 |                     | high   |
| batch.size                               | The producer will attempt to batch records together into fewer requests whenever multiple records are being sent to the same partition. This helps performance on both the client and the server. This configuration controls the default batch size in bytes.No attempt will be made to batch records larger than this size.Requests sent to brokers will contain multiple batches, one for each partition with data available to be sent.A small batch size will make batching less common and may reduce throughput (a batch size of zero will disable batching entirely). A very large batch size may use memory a bit more wastefully as we will always allocate a buffer of the specified batch size in anticipation of additional records.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | int      | 16384                                                                | \[0,...]            | medium |
| client.id                                | An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | string   | ""                                                                   |                     | medium |
| connections.max.idle.ms                  | Close idle connections after the number of milliseconds specified by this config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | long     | 540000                                                               |                     | medium |
| linger.ms                                | The producer groups together any records that arrive in between request transmissions into a single batched request. Normally this occurs only under load when records arrive faster than they can be sent out. However in some circumstances the client may want to reduce the number of requests even under moderate load. This setting accomplishes this by adding a small amount of artificial delay—that is, rather than immediately sending out a record the producer will wait for up to the given delay to allow other records to be sent so that the sends can be batched together. This can be thought of as analogous to Nagle's algorithm in TCP. This setting gives the upper bound on the delay for batching: once we get `batch.size` worth of records for a partition it will be sent immediately regardless of this setting, however if we have fewer than this many bytes accumulated for this partition we will 'linger' for the specified time waiting for more records to show up. This setting defaults to 0 (i.e. no delay). Setting `linger.ms=5`, for example, would have the effect of reducing the number of requests sent but would add up to 5ms of latency to records sent in the absense of load.         | long     | 0                                                                    | \[0,...]            | medium |
| max.block.ms                             | The configuration controls how long`KafkaProducer.send()` and`KafkaProducer.partitionsFor()` will block.These methods can be blocked either because the buffer is full or metadata unavailable.Blocking in the user-supplied serializers or partitioner will not be counted against this timeout.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | long     | 60000                                                                | \[0,...]            | medium |
| max.request.size                         | The maximum size of a request in bytes. This is also effectively a cap on the maximum record size. Note that the server has its own cap on record size which may be different from this. This setting will limit the number of record batches the producer will send in a single request to avoid sending huge requests.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 1048576                                                              | \[0,...]            | medium |
| partitioner.class                        | Partitioner class that implements the`Partitioner` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | class    | class org.apache.kafka.clients.producer.internals.DefaultPartitioner |                     | medium |
| receive.buffer.bytes                     | The size of the TCP receive buffer (SO\_RCVBUF) to use when reading data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | int      | 32768                                                                | \[0,...]            | medium |
| request.timeout.ms                       | The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 30000                                                                | \[0,...]            | medium |
| sasl.kerberos.service.name               | The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | string   | null                                                                 |                     | medium |
| sasl.mechanism                           | SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | GSSAPI                                                               |                     | medium |
| security.protocol                        | Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL\_PLAINTEXT, SASL\_SSL.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | string   | PLAINTEXT                                                            |                     | medium |
| send.buffer.bytes                        | The size of the TCP send buffer (SO\_SNDBUF) to use when sending data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | int      | 131072                                                               | \[0,...]            | medium |
| ssl.enabled.protocols                    | The list of protocols enabled for SSL connections.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | list     | \[TLSv1.2, TLSv1.1, TLSv1]                                           |                     | medium |
| ssl.keystore.type                        | The file format of the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | string   | JKS                                                                  |                     | medium |
| ssl.protocol                             | The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | TLS                                                                  |                     | medium |
| ssl.provider                             | The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | string   | null                                                                 |                     | medium |
| ssl.truststore.type                      | The file format of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | string   | JKS                                                                  |                     | medium |
| timeout.ms                               | The configuration controls the maximum amount of time the server will wait for acknowledgments from followers to meet the acknowledgment requirements the producer has specified with the `acks`configuration. If the requested number of acknowledgments are not met when the timeout elapses an error will be returned. This timeout is measured on the server side and does not include the network latency of the request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | int      | 30000                                                                | \[0,...]            | medium |
| block.on.buffer.full                     | When our memory buffer is exhausted we must either stop accepting new records (block) or throw errors. By default this setting is false and the producer will no longer throw a BufferExhaustException but instead will use the`max.block.ms` value to block, after which it will throw a TimeoutException. Setting this property to true will set the `max.block.ms` to Long.MA&#x58;_&#x56;ALUE. Also if this property is set to true, parameter \_\_`metadata.fetch.timeout.ms`_ is not longer honored.\_This parameter is deprecated and will be removed in a future release. Parameter `max.block.ms` should be used instead.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | boolean  | false                                                                |                     | low    |
| interceptor.classes                      | A list of classes to use as interceptors. Implementing the `ProducerInterceptor` interface allows you to intercept (and possibly mutate) the records received by the producer before they are published to the Kafka cluster. By default, there are no interceptors.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | list     | null                                                                 |                     | low    |
| max.in.flight.requests.per.connection    | The maximum number of unacknowledged requests the client will send on a single connection before blocking. Note that if this setting is set to be greater than 1 and there are failed sends, there is a risk of message re-ordering due to retries (i.e., if retries are enabled).                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 5                                                                    | \[1,...]            | low    |
| metadata.fetch.timeout.ms                | The first time data is sent to a topic we must fetch metadata about that topic to know which servers host the topic's partitions. This fetch to succeed before throwing an exception back to the client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | 60000                                                                | \[0,...]            | low    |
| metadata.max.age.ms                      | The period of time in milliseconds after which we force a refresh of metadata even if we haven't seen any partition leadership changes to proactively discover any new brokers or partitions.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | long     | 300000                                                               | \[0,...]            | low    |
| metric.reporters                         | A list of classes to use as metrics reporters. Implementing the `MetricReporter` interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | list     | \[]                                                                  |                     | low    |
| metrics.num.samples                      | The number of samples maintained to compute metrics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | int      | 2                                                                    | \[1,...]            | low    |
| metrics.sample.window.ms                 | The window of time a metrics sample is computed over.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | long     | 30000                                                                | \[0,...]            | low    |
| reconnect.backoff.ms                     | The amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all requests sent by the consumer to the broker.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | long     | 50                                                                   | \[0,...]            | low    |
| retry.backoff.ms                         | The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | long     | 100                                                                  | \[0,...]            | low    |
| sasl.kerberos.kinit.cmd                  | Kerberos kinit command path.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | string   | /usr/bin/kinit                                                       |                     | low    |
| sasl.kerberos.min.time.before.relogin    | Login thread sleep time between refresh attempts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | long     | 60000                                                                |                     | low    |
| sasl.kerberos.ticket.renew.jitter        | Percentage of random jitter added to the renewal time.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | double   | 0.05                                                                 |                     | low    |
| sasl.kerberos.ticket.renew.window.factor | Login thread will sleep until the specified window factor of time from last refresh to ticket's expiry has been reached, at which time it will try to renew the ticket.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | double   | 0.8                                                                  |                     | low    |
| ssl.cipher.suites                        | A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol.By default all the available cipher suites are supported.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | list     | null                                                                 |                     | low    |
| ssl.endpoint.identification.algorithm    | The endpoint identification algorithm to validate server hostname using server certificate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | string   | null                                                                 |                     | low    |
| ssl.keymanager.algorithm                 | The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | string   | SunX509                                                              |                     | low    |
| ssl.trustmanager.algorithm               | The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | PKIX                                                                 |                     | low    |

For those interested in the legacy Scala producer configs, information can be found [**here**](http://kafka.apache.org/082/documentation.html#producerconfigs).

## [3.3 Consumer Configs](#consumerconfigs) <a href="#consumerconfigs" id="consumerconfigs"></a>

We introduce both the old 0.8 consumer configs and the new consumer configs respectively below.

### [3.3.1 Old Consumer Configs](#oldconsumerconfigs) <a href="#oldconsumerconfigs" id="oldconsumerconfigs"></a>

The essential old consumer configurations are the following:

* `group.id`
* `zookeeper.connect`

| **PropertyDefaultDescription** |              |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| ------------------------------ | ------------ | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| group.id                       |              | A string that uniquely identifies the group of consumer processes to which this consumer belongs. By setting the same group id multiple processes indicate that they are all part of the same consumer group.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
| zookeeper.connect              |              | Specifies the ZooKeeper connection string in the form `hostname:port` where host and port are the host and port of a ZooKeeper server. To allow connecting through other ZooKeeper nodes when that ZooKeeper machine is down you can also specify multiple hosts in the form `hostname1:port1,hostname2:port2,hostname3:port3`.The server may also have a ZooKeeper chroot path as part of it's ZooKeeper connection string which puts its data under some path in the global ZooKeeper namespace. If so the consumer should use the same chroot path in its connection string. For example to give a chroot path of `/chroot/path` you would give the connection string as`hostname1:port1,hostname2:port2,hostname3:port3/chroot/path`. |
| consumer.id                    | null         | Generated automatically if not set.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| socket.timeout.ms              | 30 \* 1000   | The socket timeout for network requests. The actual timeout set will be max.fetch.wait + socket.timeout.ms.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |
| socket.receive.buffer.bytes    | 64 \* 1024   | The socket receive buffer for network requests                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| fetch.message.max.bytes        | 1024 \* 1024 | The number of bytes of messages to attempt to fetch for each topic-partition in each fetch request. These bytes will be read into memory for each partition, so this helps control the memory used by the consumer. The fetch request size must be at least as large as the maximum message size the server allows or else it is possible for the producer to send messages larger than the consumer can fetch.                                                                                                                                                                                                                                                                                                                           |
| num.consumer.fetchers          | 1            | The number fetcher threads used to fetch data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
| auto.commit.enable             | true         | If true, periodically commit to ZooKeeper the offset of messages already fetched by the consumer. This committed offset will be used when the process fails as the position from which the new consumer will begin.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
| auto.commit.interval.ms        | 60 \* 1000   | The frequency in ms that the consumer offsets are committed to zookeeper.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| queued.max.message.chunks      | 2            | Max number of message chunks buffered for consumption. Each chunk can be up to fetch.message.max.bytes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
| rebalance.max.retries          | 4            | When a new consumer joins a consumer group the set of consumers attempt to "rebalance" the load to assign partitions to each consumer. If the set of consumers changes while this assignment is taking place the rebalance will fail and retry. This setting controls the maximum number of attempts before giving up.                                                                                                                                                                                                                                                                                                                                                                                                                    |
| fetch.min.bytes                | 1            | The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
| fetch.wait.max.ms              | 100          | The maximum amount of time the server will block before answering the fetch request if there isn't sufficient data to immediately satisfy fetch.min.bytes                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
| rebalance.backoff.ms           | 2000         | Backoff time between retries during rebalance. If not set explicitly, the value in zookeeper.sync.time.ms is used.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
| refresh.leader.backoff.ms      | 200          | Backoff time to wait before trying to determine the leader of a partition that has just lost its leader.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
| auto.offset.reset              | largest      | What to do when there is no initial offset in ZooKeeper or if an offset is out of range:                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |

* smallest : automatically reset the offset to the smallest offset
* largest : automatically reset the offset to the largest offset
* anything else: throw exception to the consumer | | consumer.timeout.ms | -1 | Throw a timeout exception to the consumer if no message is available for consumption after the specified interval | | exclude.internal.topics | true | Whether messages from internal topics (such as offsets) should be exposed to the consumer. | | client.id | group id value | The client id is a user-specified string sent in each request to help trace calls. It should logically identify the application making the request. | | zookeeper.session.timeout.ms | 6000 | ZooKeeper session timeout. If the consumer fails to heartbeat to ZooKeeper for this period of time it is considered dead and a rebalance will occur. | | zookeeper.connection.timeout.ms | 6000 | The max time that the client waits while establishing a connection to zookeeper. | | zookeeper.sync.time.ms | 2000 | How far a ZK follower can be behind a ZK leader | | offsets.storage | zookeeper | Select where offsets should be stored (zookeeper or kafka). | | offsets.channel.backoff.ms | 1000 | The backoff period when reconnecting the offsets channel or retrying failed offset fetch/commit requests. | | offsets.channel.socket.timeout.ms | 10000 | Socket timeout when reading responses for offset fetch/commit requests. This timeout is also used for ConsumerMetadata requests that are used to query for the offset manager. | | offsets.commit.max.retries | 5 | Retry the offset commit up to this many times on failure. This retry count only applies to offset commits during shut-down. It does not apply to commits originating from the auto-commit thread. It also does not apply to attempts to query for the offset coordinator before committing offsets. i.e., if a consumer metadata request fails for any reason, it will be retried and that retry does not count toward this limit. | | dual.commit.enabled | true | If you are using "kafka" as offsets.storage, you can dual commit offsets to ZooKeeper (in addition to Kafka). This is required during migration from zookeeper-based offset storage to kafka-based offset storage. With respect to any given consumer group, it is safe to turn this off after all instances within that group have been migrated to the new version that commits offsets to the broker (instead of directly to ZooKeeper). | | partition.assignment.strategy | range | Select between the "range" or "roundrobin" strategy for assigning partitions to consumer streams.The round-robin partition assignor lays out all the available partitions and all the available consumer threads. It then proceeds to do a round-robin assignment from partition to consumer thread. If the subscriptions of all consumer instances are identical, then the partitions will be uniformly distributed. (i.e., the partition ownership counts will be within a delta of exactly one across all consumer threads.) Round-robin assignment is permitted only if: (a) Every topic has the same number of streams within a consumer instance (b) The set of subscribed topics is identical for every consumer instance within the group.Range partitioning works on a per-topic basis. For each topic, we lay out the available partitions in numeric order and the consumer threads in lexicographic order. We then divide the number of partitions by the total number of consumer streams (threads) to determine the number of partitions to assign to each consumer. If it does not evenly divide, then the first few consumers will have one extra partition. |

More details about consumer configuration can be found in the scala class`kafka.consumer.ConsumerConfig`.

### [3.3.2 New Consumer Configs](#newconsumerconfigs) <a href="#newconsumerconfigs" id="newconsumerconfigs"></a>

Since 0.9.0.0 we have been working on a replacement for our existing simple and high-level consumers. The code is considered beta quality. Below is the configuration for the new consumer:

| **NameDescriptionTypeDefaultValid ValuesImportance** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |          |                                                    |                           |        |
| ---------------------------------------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------- | -------------------------------------------------- | ------------------------- | ------ |
| bootstrap.servers                                    | A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form`host1:port1,host2:port2,...`. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down).                                                                                        | list     |                                                    |                           | high   |
| key.deserializer                                     | Deserializer class for key that implements the `Deserializer`interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | class    |                                                    |                           | high   |
| value.deserializer                                   | Deserializer class for value that implements the `Deserializer`interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | class    |                                                    |                           | high   |
| fetch.min.bytes                                      | The minimum amount of data the server should return for a fetch request. If insufficient data is available the request will wait for that much data to accumulate before answering the request. The default setting of 1 byte means that fetch requests are answered as soon as a single byte of data is available or the fetch request times out waiting for data to arrive. Setting this to something greater than 1 will cause the server to wait for larger amounts of data to accumulate which can improve server throughput a bit at the cost of some additional latency.                                                                                                                           | int      | 1                                                  | \[0,...]                  | high   |
| group.id                                             | A unique string that identifies the consumer group this consumer belongs to. This property is required if the consumer uses either the group management functionality by using`subscribe(topic)` or the Kafka-based offset management strategy.                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | ""                                                 |                           | high   |
| heartbeat.interval.ms                                | The expected time between heartbeats to the consumer coordinator when using Kafka's group management facilities. Heartbeats are used to ensure that the consumer's session stays active and to facilitate rebalancing when new consumers join or leave the group. The value must be set lower than`session.timeout.ms`, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances.                                                                                                                                                                                                                                   | int      | 3000                                               |                           | high   |
| max.partition.fetch.bytes                            | The maximum amount of data per-partition the server will return. The maximum total memory used for a request will be `#partitions * max.partition.fetch.bytes`. This size must be at least as large as the maximum message size the server allows or else it is possible for the producer to send messages larger than the consumer can fetch. If that happens, the consumer can get stuck trying to fetch a large message on a certain partition.                                                                                                                                                                                                                                                        | int      | 1048576                                            | \[0,...]                  | high   |
| session.timeout.ms                                   | The timeout used to detect failures when using Kafka's group management facilities. When a consumer's heartbeat is not received within the session timeout, the broker will mark the consumer as failed and rebalance the group. Since heartbeats are sent only when poll() is invoked, a higher session timeout allows more time for message processing in the consumer's poll loop at the cost of a longer time to detect hard failures. See also `max.poll.records`for another option to control the processing time in the poll loop. Note that the value must be in the allowable range as configured in the broker configuration by`group.min.session.timeout.ms`and`group.max.session.timeout.ms`. | int      | 30000                                              |                           | high   |
| ssl.key.password                                     | The password of the private key in the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | password | null                                               |                           | high   |
| ssl.keystore.location                                | The location of the key store file. This is optional for client and can be used for two-way authentication for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | string   | null                                               |                           | high   |
| ssl.keystore.password                                | The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | password | null                                               |                           | high   |
| ssl.truststore.location                              | The location of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | string   | null                                               |                           | high   |
| ssl.truststore.password                              | The password for the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | password | null                                               |                           | high   |
| auto.offset.reset                                    | What to do when there is no initial offset in Kafka or if the current offset does not exist any more on the server (e.g. because that data has been deleted):earliest: automatically reset the offset to the earliest offsetlatest: automatically reset the offset to the latest offsetnone: throw exception to the consumer if no previous offset is found for the consumer's groupanything else: throw exception to the consumer.                                                                                                                                                                                                                                                                       | string   | latest                                             | \[latest, earliest, none] | medium |
| connections.max.idle.ms                              | Close idle connections after the number of milliseconds specified by this config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | long     | 540000                                             |                           | medium |
| enable.auto.commit                                   | If true the consumer's offset will be periodically committed in the background.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | boolean  | true                                               |                           | medium |
| exclude.internal.topics                              | Whether records from internal topics (such as offsets) should be exposed to the consumer. If set to `true` the only way to receive records from an internal topic is subscribing to it.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | boolean  | true                                               |                           | medium |
| max.poll.records                                     | The maximum number of records returned in a single call to poll().                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | int      | 2147483647                                         | \[1,...]                  | medium |
| partition.assignment.strategy                        | The class name of the partition assignment strategy that the client will use to distribute partition ownership amongst consumer instances when group management is used                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | list     | \[org.apache.kafka.clients.consumer.RangeAssignor] |                           | medium |
| receive.buffer.bytes                                 | The size of the TCP receive buffer (SO\_RCVBUF) to use when reading data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | int      | 65536                                              | \[0,...]                  | medium |
| request.timeout.ms                                   | The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.                                                                                                                                                                                                                                                                                                                                                                                                                                        | int      | 40000                                              | \[0,...]                  | medium |
| sasl.kerberos.service.name                           | The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | string   | null                                               |                           | medium |
| sasl.mechanism                                       | SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | string   | GSSAPI                                             |                           | medium |
| security.protocol                                    | Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL\_PLAINTEXT, SASL\_SSL.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | string   | PLAINTEXT                                          |                           | medium |
| send.buffer.bytes                                    | The size of the TCP send buffer (SO\_SNDBUF) to use when sending data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 131072                                             | \[0,...]                  | medium |
| ssl.enabled.protocols                                | The list of protocols enabled for SSL connections.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | list     | \[TLSv1.2, TLSv1.1, TLSv1]                         |                           | medium |
| ssl.keystore.type                                    | The file format of the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | JKS                                                |                           | medium |
| ssl.protocol                                         | The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.                                                                                                                                                                                                                                                                                                                                                                                                            | string   | TLS                                                |                           | medium |
| ssl.provider                                         | The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | string   | null                                               |                           | medium |
| ssl.truststore.type                                  | The file format of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | string   | JKS                                                |                           | medium |
| auto.commit.interval.ms                              | The frequency in milliseconds that the consumer offsets are auto-committed to Kafka if `enable.auto.commit` is set to `true`.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | long     | 5000                                               | \[0,...]                  | low    |
| check.crcs                                           | Automatically check the CRC32 of the records consumed. This ensures no on-the-wire or on-disk corruption to the messages occurred. This check adds some overhead, so it may be disabled in cases seeking extreme performance.                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | boolean  | true                                               |                           | low    |
| client.id                                            | An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | string   | ""                                                 |                           | low    |
| fetch.max.wait.ms                                    | The maximum amount of time the server will block before answering the fetch request if there isn't sufficient data to immediately satisfy the requirement given by fetch.min.bytes.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | int      | 500                                                | \[0,...]                  | low    |
| interceptor.classes                                  | A list of classes to use as interceptors. Implementing the`ConsumerInterceptor` interface allows you to intercept (and possibly mutate) records received by the consumer. By default, there are no interceptors.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | list     | null                                               |                           | low    |
| metadata.max.age.ms                                  | The period of time in milliseconds after which we force a refresh of metadata even if we haven't seen any partition leadership changes to proactively discover any new brokers or partitions.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | long     | 300000                                             | \[0,...]                  | low    |
| metric.reporters                                     | A list of classes to use as metrics reporters. Implementing the`MetricReporter` interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | list     | \[]                                                |                           | low    |
| metrics.num.samples                                  | The number of samples maintained to compute metrics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int      | 2                                                  | \[1,...]                  | low    |
| metrics.sample.window.ms                             | The window of time a metrics sample is computed over.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | long     | 30000                                              | \[0,...]                  | low    |
| reconnect.backoff.ms                                 | The amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all requests sent by the consumer to the broker.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | long     | 50                                                 | \[0,...]                  | low    |
| retry.backoff.ms                                     | The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | long     | 100                                                | \[0,...]                  | low    |
| sasl.kerberos.kinit.cmd                              | Kerberos kinit command path.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | string   | /usr/bin/kinit                                     |                           | low    |
| sasl.kerberos.min.time.before.relogin                | Login thread sleep time between refresh attempts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         | long     | 60000                                              |                           | low    |
| sasl.kerberos.ticket.renew.jitter                    | Percentage of random jitter added to the renewal time.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | double   | 0.05                                               |                           | low    |
| sasl.kerberos.ticket.renew.window.factor             | Login thread will sleep until the specified window factor of time from last refresh to ticket's expiry has been reached, at which time it will try to renew the ticket.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | double   | 0.8                                                |                           | low    |
| ssl.cipher.suites                                    | A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol.By default all the available cipher suites are supported.                                                                                                                                                                                                                                                                                                                                                                                                                           | list     | null                                               |                           | low    |
| ssl.endpoint.identification.algorithm                | The endpoint identification algorithm to validate server hostname using server certificate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | string   | null                                               |                           | low    |
| ssl.keymanager.algorithm                             | The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | string   | SunX509                                            |                           | low    |
| ssl.trustmanager.algorithm                           | The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | string   | PKIX                                               |                           | low    |

## [3.4 Kafka Connect Configs](#connectconfigs) <a href="#connectconfigs" id="connectconfigs"></a>

Below is the configuration of the Kafka Connect framework.

| **NameDescriptionTypeDefaultValid ValuesImportance** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |          |                            |          |        |
| ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | -------- | -------------------------- | -------- | ------ |
| config.storage.topic                                 | kafka topic to store configs                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   |                            |          | high   |
| group.id                                             | A unique string that identifies the Connect cluster group this worker belongs to.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | string   |                            |          | high   |
| internal.key.converter                               | Converter class for internal key Connect data that implements the `Converter` interface. Used for converting data like offsets and configs.                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | class    |                            |          | high   |
| internal.value.converter                             | Converter class for offset value Connect data that implements the `Converter` interface. Used for converting data like offsets and configs.                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | class    |                            |          | high   |
| key.converter                                        | Converter class for key Connect data that implements the `Converter` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | class    |                            |          | high   |
| offset.storage.topic                                 | kafka topic to store connector offsets in                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | string   |                            |          | high   |
| status.storage.topic                                 | kafka topic to track connector and task status                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | string   |                            |          | high   |
| value.converter                                      | Converter class for value Connect data that implements the `Converter` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | class    |                            |          | high   |
| bootstrap.servers                                    | A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form`host1:port1,host2:port2,...`. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down). | list     | \[localhost:9092]          |          | high   |
| cluster                                              | ID for this cluster, which is used to provide a namespace so multiple Kafka Connect clusters or instances may co-exist while sharing a single Kafka cluster.                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | connect                    |          | high   |
| heartbeat.interval.ms                                | The expected time between heartbeats to the group coordinator when using Kafka's group management facilities. Heartbeats are used to ensure that the worker's session stays active and to facilitate rebalancing when new members join or leave the group. The value must be set lower than `session.timeout.ms`, but typically should be set no higher than 1/3 of that value. It can be adjusted even lower to control the expected time for normal rebalances.                                                                                                                                                  | int      | 3000                       |          | high   |
| session.timeout.ms                                   | The timeout used to detect failures when using Kafka's group management facilities.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | int      | 30000                      |          | high   |
| ssl.key.password                                     | The password of the private key in the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | password | null                       |          | high   |
| ssl.keystore.location                                | The location of the key store file. This is optional for client and can be used for two-way authentication for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | string   | null                       |          | high   |
| ssl.keystore.password                                | The store password for the key store file.This is optional for client and only needed if ssl.keystore.location is configured.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | password | null                       |          | high   |
| ssl.truststore.location                              | The location of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | string   | null                       |          | high   |
| ssl.truststore.password                              | The password for the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | password | null                       |          | high   |
| connections.max.idle.ms                              | Close idle connections after the number of milliseconds specified by this config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | long     | 540000                     |          | medium |
| receive.buffer.bytes                                 | The size of the TCP receive buffer (SO\_RCVBUF) to use when reading data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | int      | 32768                      | \[0,...] | medium |
| request.timeout.ms                                   | The configuration controls the maximum amount of time the client will wait for the response of a request. If the response is not received before the timeout elapses the client will resend the request if necessary or fail the request if retries are exhausted.                                                                                                                                                                                                                                                                                                                                                 | int      | 40000                      | \[0,...] | medium |
| sasl.kerberos.service.name                           | The Kerberos principal name that Kafka runs as. This can be defined either in Kafka's JAAS config or in Kafka's config.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | string   | null                       |          | medium |
| sasl.mechanism                                       | SASL mechanism used for client connections. This may be any mechanism for which a security provider is available. GSSAPI is the default mechanism.                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | string   | GSSAPI                     |          | medium |
| security.protocol                                    | Protocol used to communicate with brokers. Valid values are: PLAINTEXT, SSL, SASL\_PLAINTEXT, SASL\_SSL.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | PLAINTEXT                  |          | medium |
| send.buffer.bytes                                    | The size of the TCP send buffer (SO\_SNDBUF) to use when sending data.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | int      | 131072                     | \[0,...] | medium |
| ssl.enabled.protocols                                | The list of protocols enabled for SSL connections.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 | list     | \[TLSv1.2, TLSv1.1, TLSv1] |          | medium |
| ssl.keystore.type                                    | The file format of the key store file. This is optional for client.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | string   | JKS                        |          | medium |
| ssl.protocol                                         | The SSL protocol used to generate the SSLContext. Default setting is TLS, which is fine for most cases. Allowed values in recent JVMs are TLS, TLSv1.1 and TLSv1.2. SSL, SSLv2 and SSLv3 may be supported in older JVMs, but their usage is discouraged due to known security vulnerabilities.                                                                                                                                                                                                                                                                                                                     | string   | TLS                        |          | medium |
| ssl.provider                                         | The name of the security provider used for SSL connections. Default value is the default security provider of the JVM.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | string   | null                       |          | medium |
| ssl.truststore.type                                  | The file format of the trust store file.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | string   | JKS                        |          | medium |
| worker.sync.timeout.ms                               | When the worker is out of sync with other workers and needs to resynchronize configurations, wait up to this amount of time before giving up, leaving the group, and waiting a backoff period before rejoining.                                                                                                                                                                                                                                                                                                                                                                                                    | int      | 3000                       |          | medium |
| worker.unsync.backoff.ms                             | When the worker is out of sync with other workers and fails to catch up within worker.sync.timeout.ms, leave the Connect cluster for this long before rejoining.                                                                                                                                                                                                                                                                                                                                                                                                                                                   | int      | 300000                     |          | medium |
| access.control.allow.methods                         | Sets the methods supported for cross origin requests by setting the Access-Control-Allow-Methods header. The default value of the Access-Control-Allow-Methods header allows cross origin requests for GET, POST and HEAD.                                                                                                                                                                                                                                                                                                                                                                                         | string   | ""                         |          | low    |
| access.control.allow.origin                          | Value to set the Access-Control-Allow-Origin header to for REST API requests.To enable cross origin access, set this to the domain of the application that should be permitted to access the API, or '\*' to allow access from any domain. The default value only allows access from the domain of the REST API.                                                                                                                                                                                                                                                                                                   | string   | ""                         |          | low    |
| client.id                                            | An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.                                                                                                                                                                                                                                                                                                                                                                               | string   | ""                         |          | low    |
| metadata.max.age.ms                                  | The period of time in milliseconds after which we force a refresh of metadata even if we haven't seen any partition leadership changes to proactively discover any new brokers or partitions.                                                                                                                                                                                                                                                                                                                                                                                                                      | long     | 300000                     | \[0,...] | low    |
| metric.reporters                                     | A list of classes to use as metrics reporters. Implementing the `MetricReporter` interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.                                                                                                                                                                                                                                                                                                                                                                                 | list     | \[]                        |          | low    |
| metrics.num.samples                                  | The number of samples maintained to compute metrics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int      | 2                          | \[1,...] | low    |
| metrics.sample.window.ms                             | The window of time a metrics sample is computed over.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | long     | 30000                      | \[0,...] | low    |
| offset.flush.interval.ms                             | Interval at which to try committing offsets for tasks.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | long     | 60000                      |          | low    |
| offset.flush.timeout.ms                              | Maximum number of milliseconds to wait for records to flush and partition offset data to be committed to offset storage before cancelling the process and restoring the offset data to be committed in a future attempt.                                                                                                                                                                                                                                                                                                                                                                                           | long     | 5000                       |          | low    |
| reconnect.backoff.ms                                 | The amount of time to wait before attempting to reconnect to a given host. This avoids repeatedly connecting to a host in a tight loop. This backoff applies to all requests sent by the consumer to the broker.                                                                                                                                                                                                                                                                                                                                                                                                   | long     | 50                         | \[0,...] | low    |
| rest.advertised.host.name                            | If this is set, this is the hostname that will be given out to other workers to connect to.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | string   | null                       |          | low    |
| rest.advertised.port                                 | If this is set, this is the port that will be given out to other workers to connect to.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            | int      | null                       |          | low    |
| rest.host.name                                       | Hostname for the REST API. If this is set, it will only bind to this interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | string   | null                       |          | low    |
| rest.port                                            | Port for the REST API to listen on.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | int      | 8083                       |          | low    |
| retry.backoff.ms                                     | The amount of time to wait before attempting to retry a failed request to a given topic partition. This avoids repeatedly sending requests in a tight loop under some failure scenarios.                                                                                                                                                                                                                                                                                                                                                                                                                           | long     | 100                        | \[0,...] | low    |
| sasl.kerberos.kinit.cmd                              | Kerberos kinit command path.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | string   | /usr/bin/kinit             |          | low    |
| sasl.kerberos.min.time.before.relogin                | Login thread sleep time between refresh attempts.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | long     | 60000                      |          | low    |
| sasl.kerberos.ticket.renew.jitter                    | Percentage of random jitter added to the renewal time.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | double   | 0.05                       |          | low    |
| sasl.kerberos.ticket.renew.window.factor             | Login thread will sleep until the specified window factor of time from last refresh to ticket's expiry has been reached, at which time it will try to renew the ticket.                                                                                                                                                                                                                                                                                                                                                                                                                                            | double   | 0.8                        |          | low    |
| ssl.cipher.suites                                    | A list of cipher suites. This is a named combination of authentication, encryption, MAC and key exchange algorithm used to negotiate the security settings for a network connection using TLS or SSL network protocol.By default all the available cipher suites are supported.                                                                                                                                                                                                                                                                                                                                    | list     | null                       |          | low    |
| ssl.endpoint.identification.algorithm                | The endpoint identification algorithm to validate server hostname using server certificate.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        | string   | null                       |          | low    |
| ssl.keymanager.algorithm                             | The algorithm used by key manager factory for SSL connections. Default value is the key manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                         | string   | SunX509                    |          | low    |
| ssl.trustmanager.algorithm                           | The algorithm used by trust manager factory for SSL connections. Default value is the trust manager factory algorithm configured for the Java Virtual Machine.                                                                                                                                                                                                                                                                                                                                                                                                                                                     | string   | PKIX                       |          | low    |
| task.shutdown.graceful.timeout.ms                    | Amount of time to wait for tasks to shutdown gracefully. This is the total amount of time, not per task. All task have shutdown triggered, then they are waited on sequentially.                                                                                                                                                                                                                                                                                                                                                                                                                                   | long     | 5000                       |          | low    |

## [3.5 Kafka Streams Configs](#streamsconfigs) <a href="#streamsconfigs" id="streamsconfigs"></a>

Below is the configuration of the Kafka Streams client library.

| **NameDescriptionTypeDefaultValid ValuesImportance** |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |        |                                                                           |          |        |
| ---------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------ | ------------------------------------------------------------------------- | -------- | ------ |
| application.id                                       | An identifier for the stream processing application. Must be unique within the Kafka cluster. It is used as 1) the default client-id prefix, 2) the group-id for membership management, 3) the changelog topic prefix.                                                                                                                                                                                                                                                                                                                                                                                             | string |                                                                           |          | high   |
| bootstrap.servers                                    | A list of host/port pairs to use for establishing the initial connection to the Kafka cluster. The client will make use of all servers irrespective of which servers are specified here for bootstrapping—this list only impacts the initial hosts used to discover the full set of servers. This list should be in the form`host1:port1,host2:port2,...`. Since these servers are just used for the initial connection to discover the full cluster membership (which may change dynamically), this list need not contain the full set of servers (you may want more than one, though, in case a server is down). | list   |                                                                           |          | high   |
| client.id                                            | An id string to pass to the server when making requests. The purpose of this is to be able to track the source of requests beyond just ip/port by allowing a logical application name to be included in server-side request logging.                                                                                                                                                                                                                                                                                                                                                                               | string | ""                                                                        |          | high   |
| zookeeper.connect                                    | Zookeeper connect string for Kafka topics management.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | string | ""                                                                        |          | high   |
| key.serde                                            | Serializer / deserializer class for key that implements the `Serde` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | class  | class org.apache.kafka.common.serialization.Serdes$ByteArraySerde         |          | medium |
| partition.grouper                                    | Partition grouper class that implements the `PartitionGrouper`interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | class  | class org.apache.kafka.streams.processor.DefaultPartitionGrouper          |          | medium |
| replication.factor                                   | The replication factor for change log topics and repartition topics created by the stream processing application.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | int    | 1                                                                         |          | medium |
| state.dir                                            | Directory location for state store.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | string | /tmp/kafka-streams                                                        |          | medium |
| timestamp.extractor                                  | Timestamp extractor class that implements the`TimestampExtractor` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | class  | class org.apache.kafka.streams.processor.ConsumerRecordTimestampExtractor |          | medium |
| value.serde                                          | Serializer / deserializer class for value that implements the `Serde` interface.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | class  | class org.apache.kafka.common.serialization.Serdes$ByteArraySerde         |          | medium |
| buffered.records.per.partition                       | The maximum number of records to buffer per partition.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | int    | 1000                                                                      |          | low    |
| commit.interval.ms                                   | The frequency with which to save the position of the processor.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | long   | 30000                                                                     |          | low    |
| metric.reporters                                     | A list of classes to use as metrics reporters. Implementing the`MetricReporter` interface allows plugging in classes that will be notified of new metric creation. The JmxReporter is always included to register JMX statistics.                                                                                                                                                                                                                                                                                                                                                                                  | list   | \[]                                                                       |          | low    |
| metrics.num.samples                                  | The number of samples maintained to compute metrics.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | int    | 2                                                                         | \[1,...] | low    |
| metrics.sample.window.ms                             | The window of time a metrics sample is computed over.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | long   | 30000                                                                     | \[0,...] | low    |
| num.standby.replicas                                 | The number of standby replicas for each task.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      | int    | 0                                                                         |          | low    |
| num.stream.threads                                   | The number of threads to execute stream processing.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                | int    | 1                                                                         |          | low    |
| poll.ms                                              | The amount of time in milliseconds to block waiting for input.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | long   | 100                                                                       |          | low    |
| state.cleanup.delay.ms                               | The amount of time in milliseconds to wait before deleting state when a partition has migrated.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    | long   | 60000                                                                     |          | low    |
