# Licensed to the Apache Software Foundation (ASF) under one or more# contributor license agreements.  See the NOTICE file distributed with# this work for additional information regarding copyright ownership.# The ASF licenses this file to You under the Apache License, Version 2.0# (the "License"); you may not use this file except in compliance with# the License.  You may obtain a copy of the License at##    http://www.apache.org/licenses/LICENSE-2.0## Unless required by applicable law or agreed to in writing, software# distributed under the License is distributed on an "AS IS" BASIS,# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.# See the License for the specific language governing permissions and# limitations under the License.# see kafka.server.KafkaConfig for additional details and defaults############################# Server Basics ############################## The id of the broker. This must be set to a unique integer for each broker.#broker的全局唯一编号，不能重复broker.id=0############################# 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#listeners=PLAINTEXT://:9092#用来监听链接的端口，producer或consumer将在此端口上建立连接port=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#处理网络请求的线程数量num.network.threads=3# The number of threads that the server uses for processing requests, which may include disk I/O#用来处理磁盘IO的线程数量num.io.threads=8# The send buffer (SO_SNDBUF) used by the socket server# 发送套接字的缓冲区大小socket.send.buffer.bytes=102400# The receive buffer (SO_RCVBUF) used by the socket server# 接收套接字的缓冲区大小socket.receive.buffer.bytes=102400# The maximum size of a request that the socket server will accept (protection against OOM)# 请求套接字的缓冲区大小socket.request.max.bytes=104857600############################# Log Basics ############################## A comma separated list of directories under which to store log files# kafka运行日志存放路径log.dirs=/root/kafka_2.12-2.1.0/logs/kafka# 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.# topic在当前broker上的分片个数num.partitions=2# 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.# 用来恢复和清理data下数据的线程数量num.recovery.threads.per.data.dir=1############################# 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.#offsets.topic.replication.factor=1#transaction.state.log.replication.factor=1#transaction.state.log.min.isr=1############################# 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 excessive 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# segment文件保留的最长时间，超时将会被删除log.retention.hours=168# 滚动生成新的segment文件的最长时间log.roll.hours=168# A size-based retention policy for logs. Segments are pruned from the log unless the remaining# segments 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.# 日志文件中每个segment的大小，默认为1Glog.segment.bytes=1073741824# The interval at which log segments are checked to see if they can be deleted according# to the retention policies# 周期性检查文件大小的时间log.retention.check.interval.ms=300000# 日志清理是否打开log.cleaner.enable=true############################# 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.# broker需要使用zookeeper保存meta数据--192.168.142.145:2181,192.168.142.146:2181,192.168.142.147:2181# zookeeper.connect=localhost:2181zookeeper.connect=192.168.142.145:2181,192.168.142.146:2181,192.168.142.147:2181# Timeout in ms for connecting to zookeeper# zookeeper连接超时时间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.# partion buffer中，消息的条数达到阀值，将触发flush到磁盘log.flush.interval.messages=10000# 消息buffer的时间，达到阀值，将触发flush到磁盘log.flush.interval.ms=3000#删除topic需要server.properties中设置delete.topic.enable=true,否则只是标记删除delete.topic.enable=true#此处的host.name为本机IP（重要），如果不改，则客户端抛出:Producer connection to localhost:9092 unsuccessful错误host.name=192.168.142.145