一、准备工作
- 安装虚拟机软件
Virtual Box - 在
Virtual Box准备三台（或以上）虚拟机node0，node1，node2，操作系统为CentOS 6.9，IP设置为192.168.3.180，192.168.3.181，192.168.3.182(参考Nginx环境搭建 的准备工作部分) - 每台虚拟机安装
jdk1.8(参考CentOS 安装JDK) - 下载 ZooKeeper
二、安装与配置
1、将zookeeper文件上传到3个节点（在真实机器操作，我使用系统的是Ubuntu）
user@linux:~$ scp zookeeper-3.4.14.tar.gz root@192.168.3.180:/root/test
user@linux:~$ scp zookeeper-3.4.14.tar.gz root@192.168.3.181:/root/test
user@linux:~$ scp zookeeper-3.4.14.tar.gz root@192.168.3.182:/root/test
2、在node0中操作，解压缩文件并放到指定的目录
[root@localhost java]# cd ~/test
[root@localhost test]# tar -zxvf zookeeper-3.4.14.tar.gz
[root@localhost test]# mv zookeeper-3.4.14 /usr/local/java/
3、配置zookeeper
[root@localhost test]# cd /usr/local/java/zookeeper-3.4.14/conf/
[root@localhost conf]# cp zoo_sample.cfg zoo.cfg
[root@localhost conf]# ls
configuration.xsl log4j.properties zoo.cfg zoo_sample.cfg
[root@localhost conf]# vim zoo.cfg
zoo.cfg配置如下
tickTime=2000
initLimit=10
syncLimit=5
dataDir=/tmp/zookeeper
clientPort=2181
#maxClientCnxns=60
...
...
- tickTime： 指定了ZooKeeper的基本时间单位（以毫秒为单位）；
- initLimit： 指定了启动zookeeper时，zookeeper实例中的随从实例同步到领导实例的初始化连接时间限制，超出时间限制则连接失败（以tickTime为时间单位）；
- syncLimit： 指定了zookeeper正常运行时，主从节点之间同步数据的时间限制，若超过这个时间限制，那么随从实例将会被丢弃；
- dataDir： zookeeper存放数据的目录；
- clientPort： 用于连接客户端的端口。
在文件的最后加上集群的服务器信息
server.1=192.168.3.180:2888:3888
server.2=192.168.3.181:2888:3888
server.3=192.168.3.182:2888:3888
4、创建zookeeper数据的存储目录，也就是上面配置的dataDir目录
[root@localhost bin]# mkdir /tmp/zookeeper
5、在zookeeper数据的存储目录中创建文件myid
[root@localhost bin]# cd /tmp/zookeeper
[root@localhost bin]# touch myid
6、在node1和node2中重复执行步骤2到5
7、编辑node*中的myid文件
node0 中执行：
[root@localhost bin]# echo -n "1">/tmp/zookeeper/myid
node1中执行
[root@localhost bin]# echo -n "2">/tmp/zookeeper/myid
node2中执行
[root@localhost bin]# echo -n "3">/tmp/zookeeper/myid
上面的myid设置主要是设置zoo.cfg中server.xx中的xx，例如node0是集群服务器的server.1，那么node1中的myid设置为1。
8、3个节点都启动zookeeper
[root@localhost bin]# cd /usr/local/java/zookeeper-3.4.14/bin/
[root@localhost bin]# ./zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
9、查看zookeeper运行状态
[root@localhost bin]# jps
15601 QuorumPeerMain
15666 Jps
存在QuorumPeerMain，zookeeper已成功启动
[root@localhost bin]# ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Mode: follower
看到zookeeper的状态为Mode: follower或者Mode: leader，集群服务已经成功。
10、关闭zookeeper服务
[root@localhost bin]# ./zkServer.sh stop
11、重启zookeeper服务
[root@localhost bin]# ./zkServer.sh restart
三、Ｗeb界面
四、异常解决
问题1. zookeeper启动后，jps命令看不到进程QuorumPeerMain
查看日志：
[root@localhost bin]# cat /usr/local/java/zookeeper-3.4.14/bin/zookeeper.out
2019-05-19 19:46:55,928 [myid:] - INFO [main:QuorumPeerConfig@136] - Reading configuration from: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
2019-05-19 19:46:55,934 [myid:] - ERROR [main:QuorumPeerConfig@217] - 192.168.3.180 does not have the form host:port or host:port:port or host:port:port:type
2019-05-19 19:46:55,935 [myid:] - ERROR [main:QuorumPeerMain@92] - Unexpected exception, exiting abnormally
java.lang.ArrayIndexOutOfBoundsException: 1
at org.apache.zookeeper.server.quorum.QuorumPeerConfig.parseProperties(QuorumPeerConfig.java:223)
at org.apache.zookeeper.server.quorum.QuorumPeerConfig.parse(QuorumPeerConfig.java:152)
at org.apache.zookeeper.server.quorum.QuorumPeerMain.initializeAndRun(QuorumPeerMain.java:104)
at org.apache.zookeeper.server.quorum.QuorumPeerMain.main(QuorumPeerMain.java:81)
说明是server.xx配置出了问题，配置格式应为host:port或host:port:port或host:port:port:type，配置为如下即可。
server.1=192.168.3.180:2888:3888
server.2=192.168.3.181:2888:3888
server.3=192.168.3.182:2888:3888
问题2. 所有节点成功启动后，查看ZooKeeper的运行状态，报以下错误信息
[root@localhost bin]# ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Error contacting service. It is probably not running.
解决方法:
先查看日志
[root@localhost bin]# cat /usr/local/java/zookeeper-3.4.14/bin/zookeeper.out
java.net.NoRouteToHostException: 没有到主机的路由 (Host unreachable)
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:350)
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:206)
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:188)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)
at java.net.Socket.connect(Socket.java:589)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectOne(QuorumCnxManager.java:558)
at org.apache.zookeeper.server.quorum.QuorumCnxManager.connectAll(QuorumCnxManager.java:610)
at org.apache.zookeeper.server.quorum.FastLeaderElection.lookForLeader(FastLeaderElection.java:838)
at org.apache.zookeeper.server.quorum.QuorumPeer.run(QuorumPeer.java:958)
2019-05-19 17:41:17,553 [myid:2] - INFO [QuorumPeer[myid=2]/0:0:0:0:0:0:0:0:2181:QuorumPeer$QuorumServer@185] - Resolved hostname: 192.168.3.182 to address: /192.168.3.182
2019-05-19 17:41:17,553 [myid:2] - INFO [QuorumPeer[myid=2]/0:0:0:0:0:0:0:0:2181:FastLeaderElection@847] - Notification time out: 60000
日志中有一个异常信息没有到主机的路由，也就是服务器之间通讯有问题。
- 尝试
ping一下，相互能ping通，那服务器节点的IP设置没有问题，如果不能通，先把IP设置好。 - 查看防火墙是否开启
[root@localhost bin]# service iptables status
表格：filter
Chain INPUT (policy ACCEPT)
num target prot opt source destination
1 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
2 ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
3 ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
4 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
5 ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:80
6 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
num target prot opt source destination
1 REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain OUTPUT (policy ACCEPT)
num target prot opt source destination
- 尝试关闭防火墙，然后重启
zookeeper
[root@localhost bin]# service iptables stop
iptables：将链设置为政策 ACCEPT：filter [确定]
iptables：清除防火墙规则： [确定]
iptables：正在卸载模块： [确定]
[root@localhost bin]# ./zkServer.sh restart
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@localhost bin]# ./zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /usr/local/java/zookeeper-3.4.14/bin/../conf/zoo.cfg
Mode: follower
看到zookeeper的状态为Mode: follower或者Mode: leader，那么问题就已经解决，多说一句，这里解决问题是把防火墙关了，生产环境不能这么干，应该是配置防火墙信息，一般由运维来负责。
