ZooKeeper

ZooKeeper是一个分布式的，开放源码的分布式应用程序协调服务，是Google的Chubby一个开源的实现，是Hadoop和Hbase的重要组件。它是一个为分布式应用提供一致性服务的软件，提供的功能包括：配置维护、域名服务、分布式同步、组服务等。（百度百科）

1、下载与解压

下载：apache-zookeeper-3.5.5.tar.gz

解压：tar -xzvf apache-zookeeper-3.5.5.tar.gz -C /usr/local/zookeeper

进入：cd /usr/local/zookeeper/apache-zookeeper-3.5.5/

命令：

2、启动

2.1、单个节点启动

2.1.1、配置

cat conf/zoo.cfg

dataDir=/var/zookeeper

clientPort=2181

2.1.2、启动

bin/zkServer.sh start

查看进程：

未发现服务成功启动！查看日志如下：

cat logs/zookeeper-root-server-localhost.out

错误: 找不到或无法加载主类 org.apache.zookeeper.server.quorum.QuorumPeerMain

查看cat README.md文件：需要mvn打包源码生成jar包，注意跳过测试类（太耗时！）

mvn clean install -DskipTests

再次启动：

bin/zkServer.sh start

2.1.3、客户端连接

连接服务端：

bin/zkCli.sh -server localhost:2181

查看节点：

[zk: localhost:2181(CONNECTED) 4] ls /

[zookeeper]

创建节点：

[zk: localhost:2181(CONNECTED) 5] create /zk_test my_data

Created /zk_test

[zk: localhost:2181(CONNECTED) 6] ls /

[zk_test, zookeeper]

[zk: localhost:2181(CONNECTED) 7] get /zk_test

my_data

修改节点：

[zk: localhost:2181(CONNECTED) 8] set /zk_test junk

[zk: localhost:2181(CONNECTED) 9] get /zk_test

junk

删除节点：

[zk: localhost:2181(CONNECTED) 11] delete /zk_test

junk

2.2、多个节点启动

2.2.1、配置

序号	服务与端口	数据目录
1	192.168.220.13:2181	/var /zookeeper
2	192.168.220.14:2181	/var /zookeeper
3	192.168.220.15:2181	/var /zookeeper

zoo.cfg配置文件：

# The number of milliseconds of each tick

tickTime=2000

# The number of ticks that the initial

# synchronization phase can take

initLimit=10

# The number of ticks that can pass between

# sending a request and getting an acknowledgement

syncLimit=5

# the directory where the snapshot is stored.

# do not use /tmp for storage, /tmp here is just

# example sakes.

dataDir=/var/zookeeper

# the port at which the clients will connect

clientPort=2181

server.1=192.168.229.13:2888:3888

server.2=192.168.229.14:2888:3888

server.3=192.168.229.15:2888:3888

# the maximum number of client connections.

# increase this if you need to handle more clients

#maxClientCnxns=60

# Be sure to read the maintenance section of the

# administrator guide before turning on autopurge.

# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance

# The number of snapshots to retain in dataDir

#autopurge.snapRetainCount=3

# Purge task interval in hours

# Set to "0" to disable auto purge feature

#autopurge.purgeInterval=1

分别在每个服务器/var /zookeeper下创建myid文件，内容如下：

1,2,3（对应zoo.cfg中的server.x）。

端口说明：

1、2181：对cline端提供服务

2、3888：选举leader使用

3、2888：集群内机器通讯使用（Leader监听此端口）

zk各节点防火墙设置：

-A INPUT -m state --state NEW -m tcp -p tcp --dport 2181 -j ACCEPT

-A INPUT -m state --state NEW -m tcp -p tcp --dport 2888 -j ACCEPT

-A INPUT -m state --state NEW -m tcp -p tcp --dport 3888 -j ACCEPT

2.2.2、启动

登录各节点启动服务：bin/zkServer.sh start

节点操作：bin/zkCli.sh -server 192.168.229.13:2181

[zk: 192.168.229.13:2181(CONNECTED) 5] ls /

[admin, brokers, cluster, config, consumers, controller, controller_epoch, isr_change_notification, latest_producer_id_block, log_dir_event_notification, zookeeper]

[zk: 192.168.229.13:2181(CONNECTED) 6] create /zk_test zk_test_data

Created /zk_test

[zk: 192.168.229.13:2181(CONNECTED) 7] ls /

[admin, brokers, cluster, config, consumers, controller, controller_epoch, isr_change_notification, latest_producer_id_block, log_dir_event_notification, zk_test, zookeeper]

[zk: 192.168.229.13:2181(CONNECTED) 8] get /zk_test

zk_test_data

[zk: 192.168.229.13:2181(CONNECTED) 9] set /zk_test my_data

[zk: 192.168.229.13:2181(CONNECTED) 10] get /zk_test