Linux Zookeeper集群安装

由于只有一台电脑，所以搭建一个伪集群（伪集群就是在一台电脑上模拟搭建集群，走不同端口启动，真实的情况在每台机器上搭建一个zookeeper或者每台机器两个zookeeper等），道理是一样的，只不过要注意别被防火墙或者安全组规则挡住了zookeeper节点间的通信，每个节点直接的网络要是通的。
集群数量推荐奇数，这是由于zookeeper的选举规则决定的，不懂先看zookeeper入门的文章，这里只是安装教程。

1. 下载并解压zookeeper tar包

   https://apache.claz.org/zookeeper/zookeeper-3.6.2/apache-zookeeper-3.6.2-bin.tar.gz

   此处将包下载解压到了/usr/local/share/下

   #解压后的目录里的结构
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin# ls
   bin  conf  docs  lib  LICENSE.txt  logs  NOTICE.txt  README.md  README_packaging.md
   #bin目录
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin# cd bin
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/bin# ls
   README.txt    zkCli.cmd  zkEnv.cmd  zkServer.cmd            zkServer.sh            zkSnapShotToolkit.sh  zkTxnLogToolkit.sh
   zkCleanup.sh  zkCli.sh   zkEnv.sh   zkServer-initialize.sh  zkSnapShotToolkit.cmd  zkTxnLogToolkit.cmd
   #conf目录
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/conf# ls
   configuration.xsl  log4j.properties   zoo_sample.cfg
   #将bin目录添加到path去
   echo 'export PATH=$PATH:/usr/local/share/apache-zookeeper-3.6.2-bin/bin' >> /etc/profile
   #加载
   source /etc/profile
   

2. 复制三份配置后面用三份不同配置启动三个zookeeper

   #进conf目录
   cd conf
   #编辑第一个配置文件（或者复制zoo_sample.cfg修改）
   vi zk1.cfg
   

   往配置文件里写入以下内容

   # The number of milliseconds of each tick
   tickTime=2000
   # The number of ticks that the initial 
   # synchronization phase can take
   initLimit=10
   # The number of ticks that can pass between 
   # sending a request and getting an acknowledgement
   syncLimit=5
   # the directory where the snapshot is stored.
   # do not use /tmp for storage, /tmp here is just 
   # example sakes.
   dataDir=/usr/local/zk1
   # the port at which the clients will connect
   clientPort=2181
   # 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
   server.1=127.0.0.1:2981:2982
   server.2=127.0.0.1:2983:2984
   server.3=127.0.0.1:2985:2986
   

   • 然后保存退出
   • 然后复制两份，命名为zk2.cfg和zk3.cfg

   cp zk1.cfg zk2.cfg
   cp zk1.cfg zk3.cfg
   #然后编辑zk2.cfg修改dataDir为/usr/local/zk2  修改clientPort为2182
   #然后编辑zk3.cfg修改dataDir为/usr/local/zk3  修改clientPort为2183
   #均保存退出
   #创建这三个data目录
   mkdir /usr/local/zk1 /usr/local/zk2 /usr/local/zk3
   

3. 启动三个zookeeper并查看状态

   #在conf目录下执行 root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/conf
   zkServer.sh start zk1.cfg
   zkServer.sh start zk2.cfg
   zkServer.sh start zk3.cfg
   

   #查看三个zookeeper的状态，发现第二个是leader
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/conf# zkServer.sh status zk1.cfg 
   /usr/bin/java
   ZooKeeper JMX enabled by default
   Using config: /usr/local/share/apache-zookeeper-3.6.2-bin/bin/../conf/zk1.cfg
   Client port found: 2181. Client address: localhost. Client SSL: false.
   Mode: follower
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/conf# zkServer.sh status zk2.cfg 
   /usr/bin/java
   ZooKeeper JMX enabled by default
   Using config: /usr/local/share/apache-zookeeper-3.6.2-bin/bin/../conf/zk2.cfg
   Client port found: 2182. Client address: localhost. Client SSL: false.
   Mode: leader
   root@ubuntu:/usr/local/share/apache-zookeeper-3.6.2-bin/conf# zkServer.sh status zk3.cfg 
   /usr/bin/java
   ZooKeeper JMX enabled by default
   Using config: /usr/local/share/apache-zookeeper-3.6.2-bin/bin/../conf/zk3.cfg
   Client port found: 2183. Client address: localhost. Client SSL: false.
   Mode: follower
   

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