ZooKeeper集群

系统版本：CentOS Linux release 8.3.2011

JDK版本：1.8

Zookpeer版本：3.7.0

此次搭建的集群为伪集群，即在一台机器上开3个实例。

1. 下载安装包

   [root@i-h0xe1oiq tools]# wget https://dlcdn.apache.org/zookeeper/zookeeper-3.7.0/apache-zookeeper-3.7.0-bin.tar.gz
   

2. 解压安装包

   [root@i-h0xe1oiq tools]# tar xf apache-zookeeper-3.7.0-bin.tar.gz -C /application/
   

3. 查看解压后的目录

   [root@i-h0xe1oiq apache-zookeeper-3.7.0-bin]# tree -L 1
   .
   ├── bin
   ├── conf
   ├── docs
   ├── lib
   ├── LICENSE.txt
   ├── NOTICE.txt
   ├── README.md
   └── README_packaging.md
   
   4 directories, 4 files
   

4. 准备配置文件，进入conf目录，创建zoo.cfg文件，内容可复制conf/zoo_sample.cfg。

   [root@i-h0xe1oiq conf]# cp zoo_sample.cfg zoo.cfg
   

5. 配置文件说明

   # The number of milliseconds of each tick
   tickTime=2000
   # CS通信心跳数，Zookeeper 服务器之间或客户端与服务器之间维持心跳的时间间隔，也就是每个 tickTime 时间就会发送一个心跳。tickTime以毫秒为单位。
   # The number of ticks that the initial 
   # synchronization phase can take
   initLimit=10
   # LF初始通信时限，集群中的follower服务器(F)与leader服务器(L)之间初始连接时能容忍的最多心跳数（tickTime的数量）。
   # The number of ticks that can pass between 
   # sending a request and getting an acknowledgement
   syncLimit=5
   # LF同步通信时限，集群中的follower服务器与leader服务器之间请求和应答之间能容忍的最多心跳数（tickTime的数量）。
   # the directory where the snapshot is stored.
   # do not use /tmp for storage, /tmp here is just 
   # example sakes.
   dataDir=/tmp/zookeeper
   # 数据文件目录，Zookeeper保存数据的目录，默认情况下，Zookeeper将写数据的日志文件也保存在这个目录里。
   # the port at which the clients will connect
   clientPort=2181
   # 客户端连接端口，客户端连接 Zookeeper 服务器的端口，Zookeeper 会监听这个端口，接受客户端的访问请求。
   # the maximum number of client connections.
   # increase this if you need to handle more clients
   #maxClientCnxns=60
   #
   # Be sure to read the maintenance section of the 
   # administrator guide before turning on autopurge.
   #
   # http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
   #
   # The number of snapshots to retain in dataDir
   #autopurge.snapRetainCount=3
   # Purge task interval in hours
   # Set to "0" to disable auto purge feature
   #autopurge.purgeInterval=1
   
   ## Metrics Providers
   #
   # https://prometheus.io Metrics Exporter
   #metricsProvider.className=org.apache.zookeeper.metrics.prometheus.PrometheusMetricsProvider
   #metricsProvider.httpPort=7000
   #metricsProvider.exportJvmInfo=true
   
   # 服务器名称与地址：集群信息（服务器编号，服务器地址，LF通信端口，选举端口）
   # 这个配置项的书写格式比较特殊，规则如下：
   
   # server.N=YYY:A:B  
   
   # 其中N表示服务器编号，YYY表示服务器的IP地址，A为LF通信端口，表示该服务器与集群中的leader交换的信息的端口。B为选举端口，表示选举新leader时服务器间相互通信的端口（当leader挂掉时，其余服务器会相互通信，选择出新的leader）。一般来说，集群中每个服务器的A端口都是一样，每个服务器的B端口也是一样。但是当所采用的为伪集群时，IP地址都一样，只能时A端口和B端口不一样。
   

6. 伪集群准备三份zookeeper实例

   [root@i-h0xe1oiq application]# ll -h
   total 12K
   drwxr-xr-x 17 cloud-user cloud-user 4.0K Mar 17  2021 apache-zookeeper-3.7.0-2181
   drwxr-xr-x 17 root       root       4.0K Oct 25 14:54 apache-zookeeper-3.7.0-2182
   drwxr-xr-x 17 root       root       4.0K Oct 25 14:54 apache-zookeeper-3.7.0-2183
   

7. 各实例配置文件

   # 实例1
   tickTime=2000
   initLimit=10
   syncLimit=5
   dataDir=/application/apache-zookeeper-3.7.0-2181/data
   clientPort=2181
   server.1=127.0.0.1:12888:13888
   server.2=127.0.0.1:14888:15888
   server.3=127.0.0.1:16888:17888
   
   # 实例2
   tickTime=2000
   initLimit=10
   syncLimit=5
   dataDir=/application/apache-zookeeper-3.7.0-2182/data
   clientPort=2182
   server.1=127.0.0.1:12888:13888
   server.2=127.0.0.1:14888:15888
   server.3=127.0.0.1:16888:17888
   
   # 实例3
   tickTime=2000
   initLimit=10
   syncLimit=5
   dataDir=/application/apache-zookeeper-3.7.0-2183/data
   clientPort=2183
   server.1=127.0.0.1:12888:13888
   server.2=127.0.0.1:14888:15888
   server.3=127.0.0.1:16888:17888
   

8. 配置实例ID以区分

   # 实例1
   [root@i-h0xe1oiq application]# mkdir -p apache-zookeeper-3.7.0-2181/data/ && echo 1 > apache-zookeeper-3.7.0-2181/data/myid
   
   # 实例2
   [root@i-h0xe1oiq application]# mkdir -p apache-zookeeper-3.7.0-2182/data/ && echo 2 > apache-zookeeper-3.7.0-2182/data/myid
   
   # 实例3
   [root@i-h0xe1oiq application]# mkdir -p apache-zookeeper-3.7.0-2183/data/ && echo 3 > apache-zookeeper-3.7.0-2183/data/myid
   

9. 启动节点

   [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2181/bin/zkServer.sh start
   ZooKeeper JMX enabled by default
   Using config: /application/apache-zookeeper-3.7.0-2181/bin/../conf/zoo.cfg
   Starting zookeeper ... STARTED
   [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2182/bin/zkServer.sh start
   ZooKeeper JMX enabled by default
   Using config: /application/apache-zookeeper-3.7.0-2182/bin/../conf/zoo.cfg
   Starting zookeeper ... STARTED
   [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2183/bin/zkServer.sh start
   ZooKeeper JMX enabled by default
   Using config: /application/apache-zookeeper-3.7.0-2183/bin/../conf/zoo.cfg
   Starting zookeeper ... STARTED
   

10. 查看节点状态

    [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2181/bin/zkServer.sh status
    ZooKeeper JMX enabled by default
    Using config: /application/apache-zookeeper-3.7.0-2181/bin/../conf/zoo.cfg
    Client port found: 2181. Client address: localhost. Client SSL: false.
    Mode: follower
    [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2182/bin/zkServer.sh status
    ZooKeeper JMX enabled by default
    Using config: /application/apache-zookeeper-3.7.0-2182/bin/../conf/zoo.cfg
    Client port found: 2182. Client address: localhost. Client SSL: false.
    Mode: leader
    [root@i-h0xe1oiq application]# ./apache-zookeeper-3.7.0-2183/bin/zkServer.sh status
    ZooKeeper JMX enabled by default
    Using config: /application/apache-zookeeper-3.7.0-2183/bin/../conf/zoo.cfg
    Client port found: 2183. Client address: localhost. Client SSL: false.
    Mode: follower