[Hadoop] Zookeeper伪分布式集群部署

1. Zookeeper集群概念

ZK集群：3个节点，一个leader，2个follower

 

2. 伪分布式集群部署

伪分布式：1台机器上面搭建多个ZK节点

2.1 解压安装zk

解压zookeeper安装包并拷贝成三份，也就是三个zk节点

[hadoop@hadoop000 app]$ cp -r zookeeper-3.4.5-cdh5.7.0 zk001
[hadoop@hadoop000 app]$ cp -r zookeeper-3.4.5-cdh5.7.0 zk002
[hadoop@hadoop000 app]$ cp -r zookeeper-3.4.5-cdh5.7.0 zk003

2.2 修改zk配置文件

分别修改三个zk节点的配置文件

# zk001
[hadoop@hadoop000 app]$ vi zk001/conf/zoo.cfg
dataDir=/home/hadoop/tmp/zookeeper001
server.1=localhost:2888:3888
server.2=localhost:2889:3889
server.3=localhost:2890:3890
clientPort=2181

# zk002
[hadoop@hadoop000 app]$ vi zk002/conf/zoo.cfg
dataDir=/home/hadoop/tmp/zookeeper002
server.1=localhost:2888:3888
server.2=localhost:2889:3889
server.3=localhost:2890:3890
clientPort=2182

# zk003
[hadoop@hadoop000 app]$ vi zk003/conf/zoo.cfg
dataDir=/home/hadoop/tmp/zookeeper003
server.1=localhost:2888:3888
server.2=localhost:2889:3889
server.3=localhost:2890:3890
clientPort=2183

# 其中，2888是服务器与zk leader(master)通信的端口，3888为leader挂掉时，重新选举leader的端口。伪分布式部署时3个zk节点都在同一台机器上，为了端口不发生冲突，所以各节点的端口号依次+1

为每个zk节点创建dataDir文件夹

[hadoop@hadoop000 app]$ mkdir ~/tmp/zookeeper001
[hadoop@hadoop000 app]$ mkdir ~/tmp/zookeeper002
[hadoop@hadoop000 app]$ mkdir ~/tmp/zookeeper003

为每个zk节点创建myid

[hadoop@hadoop000 app]$ echo 1 > ~/tmp/zookeeper001/myid
[hadoop@hadoop000 app]$ echo 2 > ~/tmp/zookeeper002/myid
[hadoop@hadoop000 app]$ echo 3 > ~/tmp/zookeeper003/myid

2.3 启动3个zk节点

启动3个zk节点，每个节点会产生一个QuorumPeerMain进程

# 启动zk001
[hadoop@hadoop000 app]$ zk001/bin/zkServer.sh start
[hadoop@hadoop000 app]$ jps
13919 QuorumPeerMain

# 启动zk002
[hadoop@hadoop000 app]$ zk002/bin/zkServer.sh start
[hadoop@hadoop000 app]$ jps
13969 QuorumPeerMain
13919 QuorumPeerMain

# 启动zk003
[hadoop@hadoop000 app]$ zk003/bin/zkServer.sh start
[hadoop@hadoop000 app]$ jps
13969 QuorumPeerMain
14036 QuorumPeerMain
13919 QuorumPeerMain
[hadoop@hadoop000 app]$

2.4 查看节点状态

查看每个节点状态，可以看到本次启动后，zk002是leader，zk001和zk003是follower

[hadoop@hadoop000 app]$ zk001/bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/app/zk001/bin/../conf/zoo.cfg
Mode: follower
[hadoop@hadoop000 app]$ zk002/bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/app/zk002/bin/../conf/zoo.cfg
Mode: leader
[hadoop@hadoop000 app]$ zk003/bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/app/zk003/bin/../conf/zoo.cfg
Mode: follower
[hadoop@hadoop000 app]$

2.5 测试集群数据

从节点zk001启动一个zk client，连接到zk server 2182端口（zk002)。并且创建一个节点，写入数据。

[hadoop@hadoop000 app]$ zk001/bin/zkCli.sh -server localhost:2182
[zk: localhost:2182(CONNECTED) 0] ls /
[zookeeper]
[zk: localhost:2182(CONNECTED) 1] create /test hellozk002
Created /test
[zk: localhost:2182(CONNECTED) 2] get /test
hellozk002
cZxid = 0x100000002
ctime = Thu Aug 16 19:53:03 CST 2018
mZxid = 0x100000002
mtime = Thu Aug 16 19:53:03 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 10
numChildren = 0
[zk: localhost:2182(CONNECTED) 3]

去节点zk002启动一个zk client，连接zk server 2183端口（zk003），可以查看到刚才创建的test节点和数据。

[hadoop@hadoop000 app]$ zk002/bin/zkCli.sh -server localhost:2183
[zk: localhost:2183(CONNECTED) 0] ls /
[zookeeper, test]
[zk: localhost:2183(CONNECTED) 1] get /test
hellozk002
cZxid = 0x100000002
ctime = Thu Aug 16 19:53:03 CST 2018
mZxid = 0x100000002
mtime = Thu Aug 16 19:53:03 CST 2018
pZxid = 0x100000002
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 10
numChildren = 0
[zk: localhost:2183(CONNECTED) 2]

2.6 测试节点挂掉情况

将leader节点zk002进程停止，查看集群中各节点选举情况

[hadoop@hadoop000 app]$ kill -9 13969

# 此时zk003变成了leader
[hadoop@hadoop000 app]$ zk002/bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/app/zk002/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.
[hadoop@hadoop000 app]$ zk003/bin/zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/app/zk003/bin/../conf/zoo.cfg
Mode: leader
[hadoop@hadoop000 app]$

集群挂掉后数据还是可以查到，集群内部容错性是可以保证的。

 

3. 分布式集群部署

真正的分布式集群部署，过程基本一致，只是不同节点上的ZK路径完全一致，配置文件要使用同样的端口号。

[hadoop@hadoop000 app]$ vi zookeeper-3.4.5-cdh5.7.0/conf/zoo.cfg
dataDir=/home/hadoop/tmp/zookeeper
server.1=hadoop000:2888:3888
server.2=hadoop001:2888:3888
server.3=hadoop002:2888:3888
clientPort=2181

每个节点上的myid还是按照上面伪分布式部署的方式，myid号每个节点不同。其他的步骤与伪分布式一模一样。