zk集群的一些基本概念

zookeeper集群搭建：

• zk集群，主从节点，心跳机制（选举模式）
• 配置数据文件 myid 1/2/3 对应 server.1/2/3
• 通过 zkCli.sh -server [ip]:[port] 命令检测集群是否配置成功

和其他大多数集群结构一样，zookeeper集群也是主从结构。搭建集群时，机器数量最低也是三台，因为小于三台就无法进行选举。选举就是当集群中的master节点挂掉之后，剩余的两台机器会进行选举，在这两台机器中选举出一台来做master节点。而当原本挂掉的master恢复正常后，也会重新加入集群当中。但是不会再作为master节点，而是作为slave节点。如下：

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单机伪分布式搭建zookeeper集群

本节介绍单机伪分布式的zookeeper安装，官方下载地址如下：

我这里使用的是3.4.11版本，所以找到相应的版本点击进去，复制到.tar.gz的下载链接到Linux上进行下载。命令如下：

[root@study-01 ~]# cd /usr/local/src/[root@study-01 /usr/local/src]# wget https://archive.apache.org/dist/zookeeper/zookeeper-3.4.11/zookeeper-3.4.11.tar.gz

下载完成之后将其解压到/usr/local/目录下：

[root@study-01 /usr/local/src]# tar -zxvf zookeeper-3.4.11.tar.gz -C /usr/local/[root@study-01 /usr/local/src]# cd ../zookeeper-3.4.11/[root@study-01 /usr/local/zookeeper-3.4.11]# lsbin        dist-maven       lib          README_packaging.txt  zookeeper-3.4.11.jar.ascbuild.xml  docs             LICENSE.txt  recipes               zookeeper-3.4.11.jar.md5conf       ivysettings.xml  NOTICE.txt   src                   zookeeper-3.4.11.jar.sha1contrib    ivy.xml          README.md    zookeeper-3.4.11.jar[root@study-01 /usr/local/zookeeper-3.4.11]#

然后给目录重命名一下：

[root@study-01 ~]# cd /usr/local/[root@study-01 /usr/local]# mv zookeeper-3.4.11/ zookeeper00

接着进行一系列的配置：

[root@study-01 /usr/local]# cd zookeeper00/[root@study-01 /usr/local/zookeeper00]# cd conf/[root@study-01 /usr/local/zookeeper00/conf]# cp zoo_sample.cfg zoo.cfg  # 拷贝官方提供的模板配置文件[root@study-01 /usr/local/zookeeper00/conf]# vim zoo.cfg  # 增加或修改成如下内容tickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper00/dataDirdataLogDir=/usr/local/zookeeper00/dataLogDirclientPort=21814lw.commands.whitelist=*server.1=192.168.190.129:2888:3888  # master节点，ip后面跟的是集群通信的端口server.2=192.168.190.129:2889:3889server.3=192.168.190.129:2890:3890[root@study-01 /usr/local/zookeeper00/conf]# cd ../[root@study-01 /usr/local/zookeeper00]# mkdir {dataDir,dataLogDir}[root@study-01 /usr/local/zookeeper00]# cd dataDir/[root@study-01 /usr/local/zookeeper00/dataDir]# vim myid  # 配置该节点的id1[root@study-01 /usr/local/zookeeper00/dataDir]#

配置完之后，拷贝多个目录出来，因为是单机的伪分布式所以需要在一台机器上安装多个zookeeper：

[root@study-01 /usr/local]# cp zookeeper00 zookeeper01 -rf[root@study-01 /usr/local]# cp zookeeper00 zookeeper02 -rf

配置 zookeeper01：

[root@study-01 /usr/local]# cd zookeeper01/conf/[root@study-01 /usr/local/zookeeper01/conf]# vim zoo.cfg  # 修改内容如下tickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper01/dataDirdataLogDir=/usr/local/zookeeper01/dataLogDirclientPort=2182  # 端口号必须要修改4lw.commands.whitelist=*server.1=192.168.190.129:2888:3888server.2=192.168.190.129:2889:3889server.3=192.168.190.129:2890:3890[root@study-01 /usr/local/zookeeper01/conf]# cd ../dataDir/[root@study-01 /usr/local/zookeeper01/dataDir]# vim myid2[root@study-01 /usr/local/zookeeper01/dataDir]#

配置 zookeeper02：

[root@study-01 /usr/local]# cd zookeeper02/conf/[root@study-01 /usr/local/zookeeper02/conf]# vim zoo.cfgtickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper02/dataDirdataLogDir=/usr/local/zookeeper02/dataLogDirclientPort=2183  # 端口号必须要修改4lw.commands.whitelist=*server.1=192.168.190.129:2888:3888server.2=192.168.190.129:2889:3889server.3=192.168.190.129:2890:3890[root@study-01 /usr/local/zookeeper02/conf]# cd ../dataDir/[root@study-01 /usr/local/zookeeper02/dataDir]# vim myid3[root@study-01 /usr/local/zookeeper02/dataDir]#

以上就在单机上配置好三个zookeeper集群节点了，现在我们来测试一下，这个伪分布式的zookeeper集群能否正常运作起来：

[root@study-01 ~]# cd /usr/local/zookeeper00/bin/[root@study-01 /usr/local/zookeeper00/bin]# ./zkServer.sh start  # 启动第一个节点ZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper00/bin/../conf/zoo.cfgStarting zookeeper ... STARTED[root@study-01 /usr/local/zookeeper00/bin]# netstat -lntp |grep java  # 查看监听的端口tcp6       0      0 192.168.190.129:3888    :::*                    LISTEN      3191/java  # 集群通信的端口tcp6       0      0 :::44793                :::*                    LISTEN      3191/javatcp6       0      0 :::2181                 :::*                    LISTEN      3191/java [root@study-01 /usr/local/zookeeper00/bin]# cd ../../zookeeper01/bin/[root@study-01 /usr/local/zookeeper01/bin]# ./zkServer.sh startZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper01/bin/../conf/zoo.cfg  # 启动第二个节点Starting zookeeper ... STARTED[root@study-01 /usr/local/zookeeper01/bin]# cd ../../zookeeper02/bin/[root@study-01 /usr/local/zookeeper02/bin]# ./zkServer.sh start  # 启动第三个节点[root@study-01 /usr/local/zookeeper02/bin]# netstat -lntp |grep java   # 查看监听的端口tcp6       0      0 192.168.190.129:2889    :::*                    LISTEN      3232/java           tcp6       0      0 :::48463                :::*                    LISTEN      3232/java           tcp6       0      0 192.168.190.129:3888    :::*                    LISTEN      3191/java           tcp6       0      0 192.168.190.129:3889    :::*                    LISTEN      3232/java           tcp6       0      0 192.168.190.129:3890    :::*                    LISTEN      3286/java           tcp6       0      0 :::44793                :::*                    LISTEN      3191/java           tcp6       0      0 :::60356                :::*                    LISTEN      3286/java           tcp6       0      0 :::2181                 :::*                    LISTEN      3191/java           tcp6       0      0 :::2182                 :::*                    LISTEN      3232/java           tcp6       0      0 :::2183                 :::*                    LISTEN      3286/java           [root@study-01 /usr/local/zookeeper02/bin]# jps  # 查看进程3232 QuorumPeerMain3286 QuorumPeerMain3191 QuorumPeerMain3497 Jps[root@study-01 /usr/local/zookeeper02/bin]#

如上，可以看到，三个节点都正常启动成功了，接下来我们进入客户端，创建一些znode，看看是否会同步到集群中的其他节点上去：

[root@study-01 /usr/local/zookeeper02/bin]# ./zkCli.sh -server localhost:2181  # 登录第一个节点的客户端[zk: localhost:2181(CONNECTED) 0] ls /[zookeeper][zk: localhost:2181(CONNECTED) 1] create /data test-dataCreated /data[zk: localhost:2181(CONNECTED) 2] ls /[zookeeper, data][zk: localhost:2181(CONNECTED) 3] quit[root@study-01 /usr/local/zookeeper02/bin]# ./zkCli.sh -server localhost:2182  # 登录第二个节点的客户端[zk: localhost:2182(CONNECTED) 0] ls /  # 可以查看到我们在第一个节点上创建的znode，代表集群中的节点能够正常同步数据[zookeeper, data][zk: localhost:2182(CONNECTED) 1] get /data  # 数据也是一致的test-datacZxid = 0x100000002ctime = Tue Apr 24 18:35:56 CST 2018mZxid = 0x100000002mtime = Tue Apr 24 18:35:56 CST 2018pZxid = 0x100000002cversion = 0dataVersion = 0aclVersion = 0ephemeralOwner = 0x0dataLength = 9numChildren = 0[zk: localhost:2182(CONNECTED) 2] quit[root@study-01 /usr/local/zookeeper02/bin]# ./zkCli.sh -server localhost:2183  # 登录第三个节点的客户端[zk: localhost:2183(CONNECTED) 0] ls /  # 第三个节点也能查看到我们在第一个节点上创建的znode[zookeeper, data][zk: localhost:2183(CONNECTED) 1] get /data  # 数据也是一致的test-datacZxid = 0x100000002ctime = Tue Apr 24 18:35:56 CST 2018mZxid = 0x100000002mtime = Tue Apr 24 18:35:56 CST 2018pZxid = 0x100000002cversion = 0dataVersion = 0aclVersion = 0ephemeralOwner = 0x0dataLength = 9numChildren = 0[zk: localhost:2183(CONNECTED) 2] quit[root@study-01 /usr/local/zookeeper02/bin]#

查看集群的状态、主从信息需要使用 ./zkServer.sh status 命令，但是多个节点的话，逐个查看有些费劲，所以我们写一个简单的shell脚本来批量执行命令。如下：

[root@study-01 ~]# vim checked.sh  # 脚本内容如下#!/bin/bash/usr/local/zookeeper00/bin/zkServer.sh status/usr/local/zookeeper01/bin/zkServer.sh status/usr/local/zookeeper02/bin/zkServer.sh status[root@study-01 ~]# sh ./checked.sh  # 执行脚本ZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper00/bin/../conf/zoo.cfgMode: follower  # 从节点ZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper01/bin/../conf/zoo.cfgMode: leader   # 主节点ZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper02/bin/../conf/zoo.cfgMode: follower[root@study-01 ~]#

到此为止，我们就成功完成了单机zookeeper伪分布式集群的搭建，并且也测试成功了。

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搭建zookeeper分布式集群

接下来，我们使用三台虚拟机来搭建zookeeper真实分布式集群，机器的ip地址如下：

• 192.168.190.128
• 192.168.190.129
• 192.168.190.130

注：三台机器都必须具备java的运行环境，并且关闭或清空防火墙规则，不想关闭防火墙的话，就需要去配置相应的防火墙规则

首先配置一下系统的hosts文件：

[root@localhost ~]# vim /etc/hosts192.168.190.128 zk000192.168.190.129 zk001192.168.190.130 zk002

把之前做伪分布式实验机器上的其他zookeeper目录删除掉，并把zookeeper目录使用rsync同步到其他机器上。如下：

[root@zk001 ~]# cd /usr/local/[root@zk001 /usr/local]# rm -rf zookeeper01[root@zk001 /usr/local]# rm -rf zookeeper02[root@zk001 /usr/local]# mv zookeeper00/ zookeeper[root@zk001 /usr/local]# rsync -av /usr/local/zookeeper/ 192.168.190.128:/usr/local/zookeeper/[root@zk001 /usr/local]# rsync -av /usr/local/zookeeper/ 192.168.190.130:/usr/local/zookeeper/

然后逐个在三台机器上都配置一下环境变量，如下：

[root@zk001 ~]# vim .bash_profile  # 增加如下内容export ZOOKEEPER_HOME=/usr/local/zookeeperPATH=$PATH:$HOME/bin:$JAVA_HOME/bin:$ZOOKEEPER_HOME/binexport PATH[root@zk001 ~]# source .bash_profile

逐个修改配置文件，zk000：

[root@zk000 ~]# cd /usr/local/zookeeper/conf/[root@zk000 /usr/local/zookeeper/conf]# vim zoo.cfg tickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper/dataDirdataLogDir=/usr/local/zookeeper/dataLogDirclientPort=21814lw.commands.whitelist=*server.1=192.168.190.128:2888:3888  # 默认server.1为master节点server.2=192.168.190.129:2888:3888server.3=192.168.190.130:2888:3888[root@zk000 /usr/local/zookeeper/conf]# cd ../dataDir/[root@zk000 /usr/local/zookeeper/dataDir]# vim myid 1[root@zk000 /usr/local/zookeeper/dataDir]#

zk001：

[root@zk001 ~]# cd /usr/local/zookeeper/conf/[root@zk001 /usr/local/zookeeper/conf]# vim zoo.cfg tickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper/dataDirdataLogDir=/usr/local/zookeeper/dataLogDirclientPort=21814lw.commands.whitelist=*server.1=192.168.190.128:2888:3888  # 默认server.1为master节点server.2=192.168.190.129:2888:3888server.3=192.168.190.130:2888:3888[root@zk001 /usr/local/zookeeper/conf]# cd ../dataDir/[root@zk001 /usr/local/zookeeper/dataDir]# vim myid 2[root@zk001 /usr/local/zookeeper/dataDir]#

zk002：

[root@zk002 ~]# cd /usr/local/zookeeper/conf/[root@zk002 /usr/local/zookeeper/conf]# vim zoo.cfg tickTime=2000initLimit=10syncLimit=5dataDir=/usr/local/zookeeper/dataDirdataLogDir=/usr/local/zookeeper/dataLogDirclientPort=21814lw.commands.whitelist=*server.1=192.168.190.128:2888:3888  # 默认server.1为master节点server.2=192.168.190.129:2888:3888server.3=192.168.190.130:2888:3888[root@zk002 /usr/local/zookeeper/conf]# cd ../dataDir/[root@zk002 /usr/local/zookeeper/dataDir]# vim myid 3[root@zk002 /usr/local/zookeeper/dataDir]#

配置完成之后，启动三台机器的zookeeper服务：

[root@zk000 ~]# zkServer.sh start[root@zk001 ~]# zkServer.sh start[root@zk002 ~]# zkServer.sh start

启动成功后，查看三个机器的集群状态信息：

[root@zk000 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: leader[root@zk000 ~]#[root@zk001 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: follower[root@zk001 ~]# [root@zk002 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: follower[root@zk002 ~]#

然后我们来测试创建znode是否会同步，进入192.168.190.128机器的客户端：

[root@zk000 ~]# zkCli.sh -server 192.168.190.128:2181[zk: 192.168.190.128:2181(CONNECTED) 0] ls /[zookeeper, data][zk: 192.168.190.128:2181(CONNECTED) 1] create /real-culster real-dataCreated /real-culster[zk: 192.168.190.128:2181(CONNECTED) 2] ls /[zookeeper, data, real-culster][zk: 192.168.190.128:2181(CONNECTED) 3] get /real-culsterreal-datacZxid = 0x300000002ctime = Tue Apr 24 20:48:32 CST 2018mZxid = 0x300000002mtime = Tue Apr 24 20:48:32 CST 2018pZxid = 0x300000002cversion = 0dataVersion = 0aclVersion = 0ephemeralOwner = 0x0dataLength = 9numChildren = 0[zk: 192.168.190.128:2181(CONNECTED) 4] quit

进入192.168.190.129机器的客户端

[root@zk000 ~]# zkCli.sh -server 192.168.190.129:2181[zk: 192.168.190.129:2181(CONNECTED) 0] ls /[zookeeper, data, real-culster][zk: 192.168.190.129:2181(CONNECTED) 1] get /real-culsterreal-datacZxid = 0x300000002ctime = Tue Apr 24 20:48:32 CST 2018mZxid = 0x300000002mtime = Tue Apr 24 20:48:32 CST 2018pZxid = 0x300000002cversion = 0dataVersion = 0aclVersion = 0ephemeralOwner = 0x0dataLength = 9numChildren = 0[zk: 192.168.190.129:2181(CONNECTED) 2] quit

进入192.168.190.130机器的客户端

[root@zk000 ~]# zkCli.sh -server 192.168.190.130:2181[zk: 192.168.190.130:2181(CONNECTED) 0] ls /[zookeeper, data, real-culster][zk: 192.168.190.130:2181(CONNECTED) 1] get /real-culsterreal-datacZxid = 0x300000002ctime = Tue Apr 24 20:48:32 CST 2018mZxid = 0x300000002mtime = Tue Apr 24 20:48:32 CST 2018pZxid = 0x300000002cversion = 0dataVersion = 0aclVersion = 0ephemeralOwner = 0x0dataLength = 9numChildren = 0[zk: 192.168.190.130:2181(CONNECTED) 2] quit

从以上的测试可以看到，在zookeeper分布式集群中，我们在任意一个节点创建的znode都会被同步的集群中的其他节点上，数据也会被一并同步。所以到此为止，我们的zookeeper分布式集群就搭建成功了。

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测试集群角色以及选举

以上我们只是测试了znode的同步，还没有测试集群中的节点选举，所以本节就来测试一下，当master节点挂掉之后看看slave节点会不会通过选举坐上master的位置。首先我们来把master节点的zookeeper服务给停掉：

[root@zk001 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: leader[root@zk001 ~]# zkServer.sh stopZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgStopping zookeeper ... STOPPED[root@zk001 ~]#

这时到其他两台机器上进行查看，可以看到有一台已经成为master节点了：

[root@zk002 ~]# zkServer.sh status  # 可以看到zk002这个节点成为了master节点ZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: leader[root@zk002 ~]# [root@zk000 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: follower[root@zk000 ~]#

然后再把停掉的节点启动起来，可以看到，该节点重新加入了集群，但是此时是以slave角色存在，而不会以master角色存在：

[root@zk001 ~]# zkServer.sh startZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgStarting zookeeper ... STARTED[root@zk001 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: follower[root@zk001 ~]#

可以看到，zk002这个节点依旧是master角色，不会被取代，所以只有在选举的时候集群中的节点才会切换角色：

[root@zk002 ~]# zkServer.sh statusZooKeeper JMX enabled by defaultUsing config: /usr/local/zookeeper/bin/../conf/zoo.cfgMode: leader[root@zk002 ~]#