zookeeper

简介

ZooKeeper是一个分布式的，开放源码的分布式应用程序协调服务，是Google的Chubby一个开源的实现，是Hadoop和Hbase的重要组件。它是一个为分布式应用提供一致性服务的软件，提供的功能包括：配置维护、域名服务、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。

ZooKeeper包含一个简单的原语集，提供Java和C的接口。

下载

http://mirrors.hust.edu.cn/apache/zookeeper/

解压

解压到指定目录下 D:\tools\zookeeper\zookeeper-3.4.10
解压后如图：本文只关心bin目录和conf目录。

修改配置

• 修改/conf下的：zoo_sample.cfg文件名，改为：zoo.cfg
• 修改：zoo.cfg默认配置

dataDir=D:\\tools\\zookeeper\\data
dataLogDir=D:\\tools\\zookeeper\\data\\dataLog

启动

方式一

进入bin目录，双击：zkServer.cmd，即可。
看到如下画面，表示运行成功

方式二

也可以在cmd命令中连接一下
进入cmd下进bin目录，输入：zkCli.cmd 127.0.0.1:2181

这样就启动成功了

伪集群搭建

将单示例复制三份，分别命名为zookeeper_1、zookeeper_2、zookeeper_3

修改配置

1. 分别修改zoo.cfg文件

• 添加server.x配置
• 修改dataDir
• 修改clientPort

zookeeper_1的zoo.cfg

# 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:\\tools\\zookeeper\\data\\d_1
dataLogDir=D:\\tools\\zookeeper\\data\\dataLog
server.1=localhost:2888:3888
server.2=localhost:2888:3888
server.3=localhost:2888:3888
# 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

zookeeper_2的zoo_2.cfg

# 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:\\tools\\zookeeper\\data\\d_2
dataLogDir=D:\\tools\\zookeeper\\data\\dataLog
server.1=localhost:2888:3888
server.2=localhost:2888:3888
server.3=localhost:2888:3888
# the port at which the clients will connect
clientPort=2182
# 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

zookeeper_3的zoo_3.cfg

# 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:\\tools\\zookeeper\\data\\d_3
dataLogDir=D:\\tools\\zookeeper\\data\\dataLog
server.1=localhost:2888:3888
server.2=localhost:2888:3888
server.3=localhost:2888:3888
# the port at which the clients will connect
clientPort=2183
# 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

创建myid文件

分别在zoo.cfg配置的dataDir路径下创建myid文件输入本实例对应的server.x的x,这里的x只能是数字

注意：

同一IP上搭建多个节点的集群时，必须要注意端口问题，端口必须不一致才行；

创建多个节点集群时，在dataDir目录下必须创建myid文件，myid文件用于zookeeper验证server序号等，myid文件只有一行，并且为当前server的序号，例如server.1的myid就是1，server2的myid就是2等。

启动伪集群

分别cmd进入示例的bin目录下，运行各自的zkserver.cmd,zkserver.cmd,zkserver.cmd

启动过程：

启动顺序为server1、server2、server3。在启动server1，server2时zk会报错，当所有节点全部启动时错误会消失。

zoo.cfg参数说明

#   心跳检查的时间 2秒  
tickTime=2000  
# 初始化时 连接到服务器端的间隔次数，总时间10*2=20秒  
initLimit=10  
# ZK Leader 和follower 之间通讯的次数，总时间5*2=10秒   
syncLimit=5  
# 存储内存中数据库快照的位置，如果不设置参数，更新事务日志将被存储到默认位置。  
dataDir=F:\\zk\\tmp\\zookeeper  
# 错误日志的存放位置  
dataLogDir=F:\\zk\\logs\\zookeeper  
  
# ZK 服务器端的监听端口  
clientPort=2181