Zookeeper学习——单机搭建Zookeeper

搭建 zk 单机与集群

本文记录如何使用单机搭建 zk 集群，使用的是 mac 系统， 本文下载的当前zk的最新的稳定版本3.4.13

官网地址：https://zookeeper.apache.org/doc/r3.4.13/zookeeperStarted.html

单机搭建过程

• 下载地址
  https://archive.apache.org/dist/zookeeper/

• 解压缩

• 生成 zoo.cfg 文件

  进入到文件目录
  /zookeeper-3.4.13/conf
  
  拷贝文件
  cp ./zoo_sample.cfg ./zoo.cfg
  

• 启动 zk server
  ./bin/zkServer.sh start
  启动日志如下：

  ZooKeeper JMX enabled by default
  Using config: /Users/wangyang/Documents/software/zookeeper/zookeeper-3.4.13/bin/../conf/zoo.cfg
  Mode: standalone
  

  查看服务器状态
  ./bin/zkServer.sh status结果Mode: standalone

集群搭建

集群模式的配置与单机的稍微有些差别，但集群中的每台机器的配置完全一致。

1. 先看下单机 zoo.cfg 文件的内容

    # The number of milliseconds of each tick
    tickTime=2000 
    # The number of ticks that the initial
    # synchronization phase can take
    initLimit=10  初始化时的同步时间 10 * 2 s = 20 s
    # The number of ticks that can pass between
    # sending a request and getting an acknowledgement
    syncLimit=5 集群间的内部数据同步时间 5 * 2 s = 10 s
    # the directory where the snapshot is stored.
    # do not use /tmp for storage, /tmp here is just
    # example sakes.
    dataDir=/tmp/zookeeper  这个目录是 zk 的数据存放目录
    # the port at which the clients will connect
    clientPort=2180  开放给客户端连接的端口号
    # 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
   

2. 拷贝一份zk目录同时修改 zoo.cfg 文件

   cp -r ./zookeeper-3.4.9 ./zookeeper-3.4.9-back0
   

   复制后的文件目录如下图
   
   修改 zoo.cfg 文件如下

   # 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=/tmp/zookeeper
   # 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
   server.1=127.0.0.1:2888:3888
   server.2=127.0.0.1:2889:3889
   server.3=127.0.0.1:2890:3890
   

   添加的集群配置如下：

   	server.1=127.0.0.1:2888:3888
   	server.2=127.0.0.1:2889:3889
   	server.3=127.0.0.1:2890:3890
   	
   	server.id=ip:port1:port2
   	id 是集群的编号，范围 （0-255）对应的在 dataDir 所在的目录下面会有一个 myid 文件，内容只有一行就是 id 值
   	ip 是我们zk服务器的ip
   	port1 是 zk 集群中 server 数据通信的端口号
   	port2 是 zk 集群中 server leader 选举的端口号
   

3. 在 dataDir 目录下 创建 myid 文件
   内容只有 当前server 对应的 id
   

4. 同样的操作复制三份
   包括zk目录，以及 myid 文件
   
   注意
   由于是在单机上配置集群，所以三个server的端口号不能重复，包括 clientPort
dataDir也不能重复

   最终的 clientPort 和 dataDir 以及 myid 分别为:

   zookeeper-3.4.13-back0 
   clientPort = 2181
   dataDir = /tmp/zookeeper0
   myid:1
   
   zookeeper-3.4.13-back1 
   clientPort = 2182
   dataDir = /tmp/zookeeper1
   myid:2
   
   zookeeper-3.4.13-back2
   clientPort = 2183
   dataDir = /tmp/zookeeper2
   myid:3
   

5. 分别启动三台服务器
   脚本如下：

   ./zookeeper-3.4.13-back0/bin/zkServer.sh start
   ./zookeeper-3.4.13-back1/bin/zkServer.sh start
   ./zookeeper-3.4.13-back2/bin/zkServer.sh start
   

   查看服务状态

   ./zookeeper-3.4.13-back0/bin/zkServer.sh status
   ./zookeeper-3.4.13-back1/bin/zkServer.sh status
   ./zookeeper-3.4.13-back2/bin/zkServer.sh status
   

   停止服务

   ./zookeeper-3.4.13-back0/bin/zkServer.sh stop
   ./zookeeper-3.4.13-back1/bin/zkServer.sh stop
   ./zookeeper-3.4.13-back2/bin/zkServer.sh stop