Zookeeper-客户端命令行操作

• 基本命令
• 实战演练

基本命令

命令基本语法	功能描述
help	显示所有操作命令
ls path [watch]	使用ls命令来查看当前znode中所包含的内容
ls2 path [watch]	查看当前节点数据并能看到更新次数等数据
create	普通创建 -s 包含序列 -e 临时节点（重启或超时就消失）
get path [watch]	获得节点的值
set	设置节点的具体值
stat	查看节点状态
delete	删除节点
rmr	递归删除节点

实战演练

1. 启动客户端

[root@hadoop02 ~]# zkCli.sh

2. 显示所有操作命令

[zk: localhost:2181(CONNECTED) 1] help
ZooKeeper -server host:port cmd args
        stat path [watch]
        set path data [version]
        ls path [watch]
        delquota [-n|-b] path
        ls2 path [watch]
        setAcl path acl
        setquota -n|-b val path
        history 
        redo cmdno
        printwatches on|off
        delete path [version]
        sync path
        listquota path
        rmr path
        get path [watch]
        create [-s] [-e] path data acl
        addauth scheme auth
        quit 
        getAcl path
        close 
        connect host:port

3. 查看当前znode中所包含的内容

[zk: localhost:2181(CONNECTED) 2] ls /
[zookeeper]

4. 查看当前节点的详细数据

[zk: localhost:2181(CONNECTED) 3] ls2 /
[zookeeper]
cZxid = 0x0
ctime = Thu Jan 01 08:00:00 CST 1970
mZxid = 0x0
mtime = Thu Jan 01 08:00:00 CST 1970
pZxid = 0x0
cversion = -1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 1

5. 分别创建两个普通节点

[zk: localhost:2181(CONNECTED) 4] create /servers "servers"
Created /servers
[zk: localhost:2181(CONNECTED) 5] create /servers/server01 "hadoop02"
Created /servers/server01

6. 获得节点的值

[zk: localhost:2181(CONNECTED) 7] get /servers/server01
hadoop02
cZxid = 0x100000003
ctime = Fri Jun 12 20:21:35 CST 2020
mZxid = 0x100000003
mtime = Fri Jun 12 20:21:35 CST 2020
pZxid = 0x100000003
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 0

7. 创建短暂节点
   1. 创建

   [zk: localhost:2181(CONNECTED) 8] create -e /servers/server02 "hadoop03"
   Created /servers/server02
   

   2. 在当前客户端可以查看到

   [zk: localhost:2181(CONNECTED) 9] ls /servers
   [server02, server01]
   

   3. 退出当前客户端然后再重启客户端

   [zk: localhost:2181(CONNECTED) 10] quit
   [root@hadoop02 ~]# zkCli.sh
   

   4. 再次查看根目录下短暂节点已经删除

   [zk: localhost:2181(CONNECTED) 0] ls /servers
   [server01]
   

8. 创建带序号的节点

[zk: localhost:2181(CONNECTED) 0] ls /servers
[server01]
[zk: localhost:2181(CONNECTED) 1] create -s /servers/server02 "hadoop03"
Created /servers/server020000000002
[zk: localhost:2181(CONNECTED) 2] create -s /servers/server03 "hadoop04"
Created /servers/server030000000003
[zk: localhost:2181(CONNECTED) 3] ls /servers
[server020000000002, server01, server030000000003]

如果原来没有序号节点，则序号从0开始依次递增。如果原节点下已经有2个节点，则再排序时从2开始，依次类推。

9. 修改节点数据值

[zk: localhost:2181(CONNECTED) 4] set /servers/server01 "hadoop01"
cZxid = 0x100000003
ctime = Fri Jun 12 20:21:35 CST 2020
mZxid = 0x10000000a
mtime = Fri Jun 12 20:33:55 CST 2020
pZxid = 0x100000003
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 0

10. 监听节点的值变化

    1. 在 hadoop02 主机上注册监听 /servers 节点数据变化

    [zk: localhost:2181(CONNECTED) 8] get /servers watch
    

    2. 在 hadoop03 主机上修改 /servers 节点的数据

    [zk: localhost:2181(CONNECTED) 5] set /servers "update"
    

    3. 观察 hadoop02 主机上收到数据变化的监听

    [zk: localhost:2181(CONNECTED) 9] 
    WATCHER::
    
    WatchedEvent state:SyncConnected type:NodeDataChanged path:/servers
    

    注意，监听数据变化的命令是一次性的，监听到之后，命令便失效了。

11. 节点的子节点变化监听（路径变化）

    1. 在 hadoop03 主机上注册监听 /servers 节点的子节点变化

    [zk: localhost:2181(CONNECTED) 8] ls /servers watch
    

    2. 在 hadoop02 主机 /servers 节点上创建子节点

    [zk: localhost:2181(CONNECTED) 9] create /servers/server04 "test"
    

    3. 观察 hadoop03 主机上收到子节点变化的监听

    [zk: localhost:2181(CONNECTED) 9] 
    WATCHER::
    
    WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/servers
    

    同样，监听命令是一次性的，监听到之后，命令便失效了。

12. 删除节点

[zk: localhost:2181(CONNECTED) 10] delete /servers/server04

13. 递归删除节点

[zk: localhost:2181(CONNECTED) 12] rmr /servers
[zk: localhost:2181(CONNECTED) 13] ls /
[zookeeper]

14. 查看节点状态

[zk: localhost:2181(CONNECTED) 14] stat /
cZxid = 0x0
ctime = Thu Jan 01 08:00:00 CST 1970
mZxid = 0x0
mtime = Thu Jan 01 08:00:00 CST 1970
pZxid = 0x100000011
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 0
numChildren = 1

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