安装kafka前先确认服务器上是否已经安装了Java和zookeeper

zookeeper的安装和配置

1. kafka的安装和配置

1.1 下载

wget https://mirrors.bfsu.edu.cn/apache/kafka/2.8.0/kafka_2.12-2.8.0.tgz

说明：kafka名中的2.12是Scala语言版本，后面的2.8.0是kafka版本，端口默认为9092

1.2 解压

tar -xzf kafka_2.12-2.8.0.tgz

1.3 修改配置文件server.properties

1.3.1 修改kafka端口

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

修改为

advertised.listeners=PLAINTEXT://IP:9092

IP为服务器IP,IP和端口是用来建议给生产者和消费者使用的，如果没有设置，将会使用listeners的配置，如果listeners也没有配置，将使用java.net.InetAddress.getCanonicalHostName()来获取这个hostname和port，对于ipv4，基本就是localhost了。

"PLAINTEXT"表示协议，可选的值有PLAINTEXT和SSL，hostname可以指定IP地址，也可以用"0.0.0.0"表示对所有的网络接口有效，如果hostname为空表示只对默认的网络接口有效。也就是说如果你没有配置advertised.listeners，就使用listeners的配置通告给消息的生产者和消费者，这个过程是在生产者和消费者获取源数据(metadata)。

1.3.2 修改日志存储路径

logDirs=/data/kafka/logs

1.3.3 修改zookeeper的集群配置

zookeeper.connect=IP1:2181,IP2:2181,IP3:2181

1.3.4 kafka集群配置

broker.id=0

默认为0，可以设置node-1:1,node-2:2，node-3:3

2. 启动Kafka

2.1 启动zookeeper

注意：必须先启动zookeeper再启动kafka，否则会报错，错误信息如下所示：

[2021-08-23 16:53:45,825] INFO Socket error occurred: localhost/0:0:0:0:0:0:0:1:2181: 拒绝连接 (org.apache.zookeeper.ClientCnxn)
[2021-08-23 16:53:46,927] INFO Opening socket connection to server localhost/0:0:0:0:0:0:0:1:2181. Will not attempt to authenticate using SASL (unknown error) (org.apache.zookeeper.ClientCnxn)

bin/zkServer.sh start

2.2 启动Kafka

bin/kafka-server-start.sh config/server.properties
bin/kafka-server-start.sh -daemon config/server.properties（-daemon以后台的方式启动）

查看9092端口状态，确保服务已经启动

2.3检查测试

2.3.1连接zookeeper

bin/zkCli.sh -server localhost:2181

zookeeper集群建好之后，通过“ls /”出来的只有zookeeper，连接kafka使用后,/ 下面多了很多信息，其中通过查看/brokers/ids可以发现已经检查到了已经安装的三台kafka的broker.id[1,2,3]。

[zk: 192.168.1.21:2181(CONNECTED) 2] ls /          
　[admin, brokers, cluster, config, consumers, controller, controller_epoch, feature, isr_change_notification, latest_producer_id_block, log_dir_event_notification, zookeeper]
　[zk: 192.168.1.21:2181(CONNECTED) 2] ls /brokers
　[ids, seqid, topics]
　[zk: 192.168.1.21:2181(CONNECTED) 3] ls /brokers/ids
　[1, 2, 3]
　[zk: 192.168.1.21:2181(CONNECTED) 4]
　

3. kafka常用命令

3.1 创建topic

bin/kafka-topics.sh --create --zookeeper IP1:2181,IP2:2181,IP3:2181 --replication-factor 3 --partitions 3 --topic gw651_upstream_drainage

replication-factor:用来设置主题的副本数。每个主题可以有多个副本，副本位于集群中不同的broker上，也就是说副本的数量不能超过broker的数量，否则创建主题时会失败。
partitions:主题分区数。kafka通过分区策略，将不同的分区分配在一个集群中的broker上，一般会分散在不同的broker上，当只有一个broker时，所有的分区就只分配到该Broker上。消息会通过负载均衡发布到不同的分区上，消费者会监测偏移量来获取哪个分区有新数据，从而从该分区上拉取消息数据。

3.2 查看topics列表

bin/kafka-topics.sh --list --zookeeper IP1:2181,IP2:2181,IP3:2181

3.3 生产指定topic消息

bin/kafka-console-producer.sh --broker-list {kafka连接地址} --topic test

3.4 消费指定topic消息

bin/kafka-console-consumer.sh --bootstrap-server {kafka连接地址} --topic test --from-beginning

3.5 删除指定topic

bin/kafka-topics.sh --delete --zookeeper IP1:2181,IP2:2181,IP3:2181 --topic test

3.6 查询消费组

bin/kafka-consumer-groups.sh --bootstrap-server {kafka连接地址} --list

3.7 查询消费组详情

kafka-consumer-groups.sh --bootstrap-server {kafka连接地址} --describe --group {消费组}

3.8 删除消费组

kafka-consumer-groups.sh --bootstrap-server {kafka连接地址} --delete --group {消费组}

4. server.properties配置信息详细说明

# 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 #############################

##################################################################################
#  broker就是一个kafka的部署实例，在一个kafka集群中，每一台kafka都要有一个broker.id
#  并且，该id唯一，且必须为整数
##################################################################################
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 = security_protocol://host_name:port
#   EXAMPLE:
#     listeners = PLAINTEXT://your.host.name:9092
#listeners=PLAINTEXT://: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

##################################################################################
#The number of threads handling network requests
# 默认处理网络请求的线程个数 3个
##################################################################################
num.network.threads=3
##################################################################################
# The number of threads doing disk I/O
# 执行磁盘IO操作的默认线程个数 8
##################################################################################
num.io.threads=8

##################################################################################
# The send buffer (SO_SNDBUF) used by the socket server
# socket服务使用的进行发送数据的缓冲区大小，默认100kb
##################################################################################
socket.send.buffer.bytes=102400

##################################################################################
# The receive buffer (SO_SNDBUF) used by the socket server
# socket服务使用的进行接受数据的缓冲区大小，默认100kb
##################################################################################
socket.receive.buffer.bytes=102400

##################################################################################
# The maximum size of a request that the socket server will accept (protection against OOM)
# socket服务所能够接受的最大的请求量，防止出现OOM(Out of memory)内存溢出，默认值为：100m
# （应该是socker server所能接受的一个请求的最大大小，默认为100M）
##################################################################################
socket.request.max.bytes=104857600

############################# Log Basics （数据相关部分，kafka的数据称为log）#############################

##################################################################################
# A comma seperated list of directories under which to store log files
# 一个用逗号分隔的目录列表，用于存储kafka接受到的数据
##################################################################################
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.
# 每一个topic所对应的log的partition分区数目，默认1个。更多的partition数目会提高消费
# 并行度，但是也会导致在kafka集群中有更多的文件进行传输
# （partition就是分布式存储，相当于是把一份数据分开几份来进行存储，即划分块、划分分区的意思）
##################################################################################
num.partitions=1

##################################################################################
# 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.
# 每一个数据目录用于在启动kafka时恢复数据和在关闭时刷新数据的线程个数。如果kafka数据存储在磁盘阵列中
# 建议此值可以调整更大。
##################################################################################
num.recovery.threads.per.data.dir=1

############################# Log Flush Policy （数据刷新策略）#############################

# 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（平衡） here:
#    1. Durability 持久性: Unflushed data may be lost if you are not using replication.
#    2. Latency 延时性: 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 吞吐量: 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.
# kafka中只有基于消息条数和时间间隔数来制定数据刷新策略，而没有大小的选项，这两个选项可以选择配置一个
# 当然也可以两个都配置，默认情况下两个都配置，配置如下。

# The number of messages to accept before forcing a flush of data to disk
# 消息刷新到磁盘中的消息条数阈值
#log.flush.interval.messages=10000

# The maximum amount of time a message can sit in a log before we force a flush
# 消息刷新到磁盘生成一个log数据文件的时间间隔
#log.flush.interval.ms=1000

############################# Log Retention Policy（数据保留策略） #############################

# The following configurations control the disposal（清理） of log segments（分片）. The policy can
# be set to delete segments after a period of time, or after a given size has accumulated（累积）.
# A segment will be deleted whenever（无论什么时间） *either* of these criteria（标准） are met. Deletion always happens
# from the end of the log.
# 下面的配置用于控制数据片段的清理，只要满足其中一个策略（基于时间或基于大小），分片就会被删除

# The minimum age of a log file to be eligible for deletion
# 基于时间的策略，删除日志数据的时间，默认保存7天
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. 1G
# 基于大小的策略，1G
#log.retention.bytes=1073741824

# The maximum size of a log segment file. When this size is reached a new log segment will be created.
# 数据分片策略
log.segment.bytes=1073741824

# The interval at which log segments are checked to see if they can be deleted according
# to the retention policies 5分钟
# 每隔多长时间检测数据是否达到删除条件
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.connect=IP1:2181,IP2:2181,IP3:2181

# Timeout in ms for connecting to zookeeper
zookeeper.connection.timeout.ms=6000