1. 概述
ZooKeeper是Hadoop的正式子项目，它是一个针对大型分布式系统的可靠协调系统，提供的功能包括：配置维护、名字服务、分布式同步、组服务等。ZooKeeper的目标就是封装好复杂易出错的关键服务，将简单易用的接口和性能高效、功能稳定的系统提供给用户。

2. 安装&配置
在apache的官方网站提供了好多镜像下载地址，然后找到对应的版本，目前最新的是3.3.6

Windows下安装

把下载的zookeeper的文件解压到指定目录
D:\machine\zookeeper-3.3.6>

修改conf下增加一个zoo.cfg
内容如下：
# The number of milliseconds of each tick 心跳间隔 毫秒每次
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 anacknowledgement
syncLimit=5
# the directory where the snapshot isstored. //镜像数据位置
dataDir=D:\\data\\zookeeper
#日志位置
dataLogDir=D:\\logs\\zookeeper
# the port at which the clients willconnect 客户端连接的端口
clientPort=2181
注：如果启动有报错提示cfg文件有错误，可以用zoo_sample.cfg内内容替代也是可以的

进入到bin目录，并且启动zkServer.cmd，这个脚本中会启动一个Java进程
D:\machine\zookeeper-3.3.6>cd bin
D:\machine\zookeeper-3.3.6\bin>
D:\machine\zookeeper-3.3.6\bin >zkServer.cmd

启动后jps可以看到QuorumPeerMain的进程
D:\machine\zookeeper-3.3.6\bin >jps

启动客户端运行查看一下
D:\machine\zookeeper-3.3.6\bin>zkCli.cmd-server 127.0.0.1:2181

这个时候zookeeper已经安装成功了。

在 一台机器上通过伪集群运行时可以修改 zkServer.cmd 文件在里面加入
set ZOOCFG=..\conf\zoo1.cfg 这行，另存为 zkServer-1.cmd

如果有多个可以以此类推

还需要 在对应的
/tmp/zookeeper/1，
/tmp/zookeeper/2，
/tmp/zookeeper/3
建立一个文本文件命名为myid，内容就为对应的zoo.cfg里server.后数字。

---

　　# 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=d:\\zookeeper\\data
datalogdir=d:\\zookeeper\\log
# 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
#