ZooKeeper的伪分布式集群搭建

ZooKeeper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：

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：

https://archive.apache.org/dist/zookeeper/

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。操作命令如下：

[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]# ls
bin        dist-maven       lib          README_packaging.txt  zookeeper-3.4.11.jar.asc
build.xml  docs             LICENSE.txt  recipes               zookeeper-3.4.11.jar.md5
conf       ivysettings.xml  NOTICE.txt   src                   zookeeper-3.4.11.jar.sha1
contrib    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=2000
initLimit=10
syncLimit=5
dataDir=/usr/local/zookeeper00/dataDir
dataLogDir=/usr/local/zookeeper00/dataLogDir
clientPort=2181
4lw.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=192.168.190.129:2889:3889
server.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id
1
[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=2000
initLimit=10
syncLimit=5
dataDir=/usr/local/zookeeper01/dataDir
dataLogDir=/usr/local/zookeeper01/dataLogDir
clientPort=2182  # 端口号必须要修改
4lw.commands.whitelist=*
server.1=192.168.190.129:2888:3888
server.2=192.168.190.129:2889:3889
server.3=192.168.190.129:2890:3890
[root@study-01 /usr/local/zookeeper01/conf]# cd ../dataDir/
[root@study-01 /usr/local/zookeeper01/dataDir]# vim myid
2
[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.cfg
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/usr/local/zookeeper02/dataDir
dataLogDir=/usr/local/zookeeper02/dataLogDir
clientPort=2183  # 端口号必须要修改
4lw.commands.whitelist=*
server.1=192.168.190.129:2888:3888
server.2=192.168.190.129:2889:3889
server.3=192.168.190.129:2890:3890
[root@study-01 /usr/local/zookeeper02/conf]# cd ../dataDir/
[root@study-01 /usr/local/zookeeper02/dataDir]# vim myid
3
[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 default
Using config: /usr/local/zookeeper00/bin/../conf/zoo.cfg
Starting 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/java
tcp6       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 start
ZooKeeper JMX enabled by default
Using 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 QuorumPeerMain
3286 QuorumPeerMain
3191 QuorumPeerMain
3497 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-data
Created /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-data
cZxid = 0x100000002
ctime = Tue Apr 24 18:35:56 CST 2018
mZxid = 0x100000002
mtime = Tue Apr 24 18:35:56 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 9
numChildren = 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-data
cZxid = 0x100000002
ctime = Tue Apr 24 18:35:56 CST 2018
mZxid = 0x100000002
mtime = Tue Apr 24 18:35:56 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 9
numChildren = 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 default
Using config: /usr/local/zookeeper00/bin/../conf/zoo.cfg
Mode: follower  # 从节点
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper01/bin/../conf/zoo.cfg
Mode: leader   # 主节点
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper02/bin/../conf/zoo.cfg
Mode: 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。