一、安装
伪分布式安装注意事项： 在伪分布式启动server端服务时，注意同时启动服务。否则会报
2017-03-10 23:46:07,445 [myid:1] - WARN [WorkerSender[myid=1]:QuorumCnxManager@400] - Cannot open channel to 3 at election address localhost/127.0.0.1:17772（当前服务进程尚未开启）
java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:381)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.toSend(QuorumCnxManager.java:354)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.process(FastLeaderElection.java:452)
at org.apache.zookeeper.server.quorum.FastLeaderElection$Messenger$WorkerSender.run(FastLeaderElection.java:433)
at java.lang.Thread.run(Thread.java:745)
2017-03-10 23:46:07,446 [myid:1] - INFO [WorkerSender[myid=1]:QuorumPeer$QuorumServer@149] - Resolved hostname: localhost to address: localhost/127.0.0.1
启动成功后：
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。
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
下载地址：
http://mirrors.cnnic.cn/apache/zookeeper/zookeeper-3.3.6/zookeeper-3.3.6.tar.gz
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，
参考官方文档：
http://zookeeper.apache.org/doc/trunk/zookeeperStarted.html
参考单机模式、集群和伪集群的帖子
http://sqcjy111.iteye.com/blog/1741320
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
