# The id of the broker. This must be set to a unique integer for each broker.

# 节点的ID，必须与其它节点不同

broker.id=0

# Switch to enable topic deletion or not, default value is false

# 选择启用删除主题功能，默认false

delete.topic.enable=true

unclean.leader.election.enable=true

############################# Socket Server Settings #############################

# The address the socket server listens on. It will get the value returned from

# java.net.InetAddress.getCanonicalHostName() if not configured.

#   FORMAT:

#     listeners = listener_name://host_name:port

#   EXAMPLE:

#     listeners = PLAINTEXT://your.host.name:9092

# 监听端口及IP

listeners=PLAINTEXT://x.x.x.x:9092

# Hostname and port the broker will advertise to producers and consumers. If not set,

# it uses the value for "listeners" if configured.  Otherwise, it will use the value

# returned from java.net.InetAddress.getCanonicalHostName().

#advertised.listeners=PLAINTEXT://your.host.name:9092

# Maps listener names to security protocols, the default is for them to be the same. See the config documentation for more details

#listener.security.protocol.map=PLAINTEXT:PLAINTEXT,SSL:SSL,SASL_PLAINTEXT:SASL_PLAINTEXT,SASL_SSL:SASL_SSL

# The number of threads that the server uses for receiving requests from the network and sending responses to the network

# 接受网络请求的线程数

num.network.threads=6

# The number of threads that the server uses for processing requests, which may include disk I/O

# 进行磁盘IO的线程数

num.io.threads=16

# The send buffer (SO_SNDBUF) used by the socket server

# 套接字服务器使用的发送缓冲区大小

socket.send.buffer.bytes=102400

# The receive buffer (SO_RCVBUF) used by the socket server

# 套接字服务器使用的接收缓冲区大小

socket.receive.buffer.bytes=102400

# The maximum size of a request that the socket server will accept (protection against OOM)

# 单个请求最大能接收的数据量

socket.request.max.bytes=104857600

############################# Log Basics #############################

# A comma seperated list of directories under which to store log files

# 一个逗号分隔的目录列表，用来存储日志文件

log.dirs=/data/kafka-logs

# The default number of log partitions per topic. More partitions allow greater

# parallelism for consumption, but this will also result in more files across

# the brokers.

# 每个主题的日志分区的默认数量。更多的分区允许更大的并行操作，但是它会导致节点产生更多的文件

num.partitions=6

# The number of threads per data directory to be used for log recovery at startup and flushing at shutdown.

# This value is recommended to be increased for installations with data dirs located in RAID array.

# 每个数据目录中的线程数，用于在启动时日志恢复，并在关闭时刷新。

num.recovery.threads.per.data.dir=4

## 是否开启日志压缩

log.cleaner.enable=true

## 是否允许控制器关闭broker ,若是设置为true,会关闭所有在这个broker上的leader，并转移到其他broker

controlled.shutdown.enable=true

#如果unclean.leader.election.enable参数的值为false，那么就意味着非ISR中的副本不能够参与选举，此时无法进行新的选举，此时整个分区处于不可用状态。如果unclean.leader.election.enable参数的值为true，那么可以从非ISR集合中选举follower副本称为新的leader。

unclean.leader.election.enable=false

## 一个topic ，默认分区的replication个数 ，不得大于集群中broker的个数

default.replication.factor=3

## 是否允许自动创建topic ，若是false，就需要通过命令创建topic

auto.create.topics.enable=false

## leader 进行复制的线程数，增大这个数值会增加follower的IO

num.replica.fetchers=2

############################# Internal Topic Settings  #############################

# The replication factor for the group metadata internal topics "__consumer_offsets" and "__transaction_state"

# For anything other than development testing, a value greater than 1 is recommended for to ensure availability such as 3.

# 内部主题设置

# 对于除了开发测试之外的其他任何东西，group元数据内部主题的复制因子“__consumer_offsets”和“__transaction_state”，建议值大于1，以确保可用性(如3)。

offsets.topic.replication.factor=3

transaction.state.log.replication.factor=3

transaction.state.log.min.isr=2

############################# Log Flush Policy #############################

# Messages are immediately written to the filesystem but by default we only fsync() to sync

# the OS cache lazily. The following configurations control the flush of data to disk.

# There are a few important trade-offs here:

#    1. Durability: Unflushed data may be lost if you are not using replication.

#    2. Latency: Very large flush intervals may lead to latency spikes when the flush does occur as there will be a lot of data to flush.

#    3. Throughput: The flush is generally the most expensive operation, and a small flush interval may lead to exceessive seeks.

# The settings below allow one to configure the flush policy to flush data after a period of time or

# every N messages (or both). This can be done globally and overridden on a per-topic basis.

# The number of messages to accept before forcing a flush of data to disk

#log.flush.interval.messages=10000

# The maximum amount of time a message can sit in a log before we force a flush

#log.flush.interval.ms=1000

############################# Log Retention Policy #############################

# The following configurations control the disposal of log segments. The policy can

# be set to delete segments after a period of time, or after a given size has accumulated.

# A segment will be deleted whenever *either* of these criteria are met. Deletion always happens

# from the end of the log.

# The minimum age of a log file to be eligible for deletion due to age

# 一个日志的最小存活时间，可以被删除

log.retention.hours=168

# A size-based retention policy for logs. Segments are pruned from the log as long as the remaining

# segments don't drop below log.retention.bytes. Functions independently of log.retention.hours.

#log.retention.bytes=1073741824

# The maximum size of a log segment file. When this size is reached a new log segment will be created.

# 每一个日志段大小的最大值。当到达这个大小时，会生成一个新的片段。

log.segment.bytes=1073741824

# The interval at which log segments are checked to see if they can be deleted according

# to the retention policies

# 检查日志段的时间间隔，看是否可以根据保留策略删除它们

log.retention.check.interval.ms=300000

############################# Zookeeper #############################

# Zookeeper connection string (see zookeeper docs for details).

# This is a comma separated host:port pairs, each corresponding to a zk

# server. e.g. "127.0.0.1:3000,127.0.0.1:3001,127.0.0.1:3002".

# You can also append an optional chroot string to the urls to specify the

# root directory for all kafka znodes.

# Zookeeper连接字符串

# 这是一个以逗号为分割的部分，每一个都匹配一个Zookeeper

# 您还可以将一个可选的chroot字符串附加到url，以指定所有kafka znode的根目录。

zookeeper.connect=192.168.1.235:2181,192.168.1.236:2181,192.168.1.237:2181

# Timeout in ms for connecting to zookeeper

# 连接到Zookeeper的超时时间

zookeeper.connection.timeout.ms=6000

############################# Group Coordinator Settings #############################

# The following configuration specifies the time, in milliseconds, that the GroupCoordinator will delay the initial consumer rebalance.

# The rebalance will be further delayed by the value of group.initial.rebalance.delay.ms as new members join the group, up to a maximum of max.poll.interval.ms.

# The default value for this is 3 seconds.

# We override this to 0 here as it makes for a better out-of-the-box experience for development and testing.

# However, in production environments the default value of 3 seconds is more suitable as this will help to avoid unnecessary, and potentially expensive, rebalances during application startup.

#让coordinator推迟空消费组接收到成员加入请求后本应立即开启的rebalance

group.initial.rebalance.delay.ms=3000