Zookeeper集群搭建详细步骤_怎么在一台虚拟机上搭建zk集群

Zookeeper集群搭建

1.1 搭建要求

真实的集群是需要部署在不同的服务器上的，但是在我们测试时同时启动很多个虚拟机内存会吃不消，所以我们通常会搭建伪集群，也就是把所有的服务都搭建在一台虚拟机上，用端口进行区分。

我们这里要求搭建一个三个节点的Zookeeper集群（伪集群）。

1.2 准备工作

需要一台Linux虚拟机作为搭建集群的测试服务器。

（1）Zookeeper压缩包上传到服务器

前面已经写过Zookeeper详细安装步骤，这里就不在写了

（2）将Zookeeper解压 ，

建立/usr/local/zookeeper-cluster目录，将解压后的Zookeeper复制到以下三个目录
/usr/local/zookeeper-cluster/zookeeper-1
/usr/local/zookeeper-cluster/zookeeper-2
/usr/local/zookeeper-cluster/zookeeper-3
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# 创建集群目录zookeeper-cluster
[root@rhel ~]# mkdir /usr/local/zookeeper-cluster

[root@rhel local]# cp -r apache-zookeeper-3.6.4-bin /usr/local/zookeeper-cluster/zookeeper-1
[root@rhel local]# cp -r apache-zookeeper-3.6.4-bin /usr/local/zookeeper-cluster/zookeeper-2
[root@rhel local]# cp -r apache-zookeeper-3.6.4-bin /usr/local/zookeeper-cluster/zookeeper-3

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（3）创建data目录 ，并且将 conf下zoo_sample.cfg 文件改名为 zoo.cfg

mkdir /usr/local/zookeeper-cluster/zookeeper-1/data
mkdir /usr/local/zookeeper-cluster/zookeeper-2/data
mkdir /usr/local/zookeeper-cluster/zookeeper-3/data

mv  /usr/local/zookeeper-cluster/zookeeper-1/conf/zoo_sample.cfg  /usr/local/zookeeper-cluster/zookeeper-1/conf/zoo.cfg
mv  /usr/local/zookeeper-cluster/zookeeper-2/conf/zoo_sample.cfg  /usr/local/zookeeper-cluster/zookeeper-2/conf/zoo.cfg
mv  /usr/local/zookeeper-cluster/zookeeper-3/conf/zoo_sample.cfg  /usr/local/zookeeper-cluster/zookeeper-3/conf/zoo.cfg
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（4） 配置每一个Zookeeper 的dataDir 和 clientPort 分别为2181 2182 2183

vim /usr/local/zookeeper-cluster/zookeeper-1/conf/zoo.cfg
#修改/usr/local/zookeeper-cluster/zookeeper-1/conf/zoo.cfg
[root@rhel zookeeper-cluster]# vim zookeeper-1/conf/zoo.cfg 

clientPort=2181
dataDir=/usr/local/zookeeper-cluster/zookeeper-1/data

#修改/usr/local/zookeeper-cluster/zookeeper-2/conf/zoo.cfg
[root@rhel zookeeper-cluster]# vim zookeeper-2/conf/zoo.cfg 

clientPort=2182
dataDir=/usr/local/zookeeper-cluster/zookeeper-2/data

#修改/usr/local/zookeeper-cluster/zookeeper-3/conf/zoo.cfg
[root@rhel zookeeper-cluster]# vim zookeeper-3/conf/zoo.cfg 

clientPort=2183
dataDir=/usr/local/zookeeper-cluster/zookeeper-3/data
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1.3 配置集群

（1）在每个zookeeper的 data 目录下创建一个 myid 文件，内容分别是1、2、3 。这个文件就是记录每个服务器的ID

echo 1 >/usr/local/zookeeper-cluster/zookeeper-1/data/myid
echo 2 >/usr/local/zookeeper-cluster/zookeeper-2/data/myid
echo 3 >/usr/local/zookeeper-cluster/zookeeper-3/data/myid
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（2）在每一个zookeeper 的 zoo.cfg配置客户端访问端口（clientPort）和集群服务器IP列表。

集群服务器IP列表如下：

vim /usr/local/zookeeper-cluster/zookeeper-1/conf/zoo.cfg
vim /usr/local/zookeeper-cluster/zookeeper-2/conf/zoo.cfg
vim /usr/local/zookeeper-cluster/zookeeper-3/conf/zoo.cfg

server.1=192.168.45.88:2881:3881
server.2=192.168.45.88:2882:3882
server.3=192.168.45.88:2883:3883

#解释：server.服务器ID=服务器IP地址：服务器之间通信端口：服务器之间投票选举端口
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1.4 启动集群

启动集群就是分别启动每个实例。

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh start
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh start
/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh start

# 启动效果如下：
[root@rhel zookeeper-cluster]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@rhel zookeeper-cluster]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@rhel zookeeper-cluster]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED

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启动后我们查询一下每个实例的运行状态

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Client port found: 2183. Client address: localhost. Client SSL: false.
Mode: follower
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Client port found: 2182. Client address: localhost. Client SSL: false.
Mode: leader
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower

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1.5 模拟集群异常

（1）首先我们先测试如果是从服务器挂掉，会怎么样

把3号服务器停掉，观察1号和2号，发现状态并没有变化

/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh stop

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh stop
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Client port found: 2182. Client address: localhost. Client SSL: false.
Mode: leader

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由此得出结论，3个节点的集群，从服务器挂掉，集群正常

（2）我们再把1号服务器（从服务器）也停掉，查看2号（主服务器）的状态，发现已经停止运行了。

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh stop
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh stop
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Client port found: 2182. Client address: localhost. Client SSL: false.
Error contacting service. It is probably not running.

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由此得出结论，3个节点的集群，2个从服务器都挂掉，主服务器也无法运行。因为可运行的机器没有超过集群总数量的半数。

（3）我们再次把1号服务器启动起来，发现2号服务器又开始正常工作了。而且依然是领导者。

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh start
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Client port found: 2182. Client address: localhost. Client SSL: false.
Mode: leader

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（4）我们把3号服务器也启动起来，把2号服务器停掉,停掉后观察1号和3号的状态。

/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh start
/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh stop

/usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh stop
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-1/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-1/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost. Client SSL: false.
Mode: follower
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Client port found: 2183. Client address: localhost. Client SSL: false.
Mode: leader

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发现新的leader产生了~

由此我们得出结论，当集群中的主服务器挂了，集群中的其他服务器会自动进行选举状态，然后产生新得leader

（5）我们再次测试，当我们把2号服务器重新启动起来启动后，会发生什么？2号服务器会再次成为新的领导吗？我们看结果

/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh start

/usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
/usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status

#测试效果
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-2/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-2/bin/../conf/zoo.cfg
Client port found: 2182. Client address: localhost. Client SSL: false.
Mode: follower
[root@rhel ~]# /usr/local/zookeeper-cluster/zookeeper-3/bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/zookeeper-cluster/zookeeper-3/bin/../conf/zoo.cfg
Client port found: 2183. Client address: localhost. Client SSL: false.
Mode: leader

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我们会发现，2号服务器启动后依然是跟随者（从服务器），3号服务器依然是领导者（主服务器），没有撼动3号服务器的领导地位。

由此我们得出结论，当领导者产生后，再次有新服务器加入集群，不会影响到现任领导者。

小结

zookeeper的安装和集群搭建，不复杂，但是需要上手实际操作，集群搭建时容易出错，这里需要注意，不操作可能不知道，主要是遇到问题，分析问题，是什么？为什么？从哪里入手？怎么改？下次怎么避免？