Zookeeper基础使用

部署和运行

脚本

ZooKeeper的bin目录下的脚本见下表

脚本	说明
zkCleanup	清理ZooKeeper历史数据，包括事务日志文件和快照数据文件
zkCli	ZooKeeper的一个简易客户端
zkEnv	设置ZooKeeper的环境变量
zkServer	ZooKeeper服务器的启动、停止和重启

启动服务

常见的启动方式有两种：

Java命令行, 在ZooKeeper目录下执行如下命令
```
java -cp zookeeper-3.4.6.jar：lib
```
使用自带脚本启动，在ZooKeeper目录下执行如下命令:
```
./bin/zkServer.sh
```

停止服务

可以使用zkServer脚本的stop命令来停止服务。

sh bin/zkServer.sh stop

基本指令

客户端连接

Zookeeper自带的脚本里有个zkCli，是ZooKeeper的一个简易客户端, 使用方式：

zkCli.sh [-server ip:port]

运行如下指令启动客户端可以连接到默认服务器localhost:2181

bin/zkCli.sh

看到下面输表明连接正常：

Connecting to localhost:2181

2019-03-27 17:05:34,602 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.6-1569965, built on 02/20/2014 09:09 GMT

2019-03-27 17:05:34,605 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=WANJP3

2019-03-27 17:05:34,605 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.8.0_20

2019-03-27 17:05:34,607 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Oracle Corporation

2019-03-27 17:05:34,608 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=C:\Program Files\Java\jre1.8.0_20

2019-03-27 17:05:34,608 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=D:\zookeeper-3.4.6\bin\..\build\classes;D:\zookeeper-3.4.6\bin\..\build\lib\*;D:\zookeeper-3.4.6\bin\..\zookeeper-3.4.6.jar;D:\zookeeper-3.4.6\bin\..\lib\jline-0.9.94.jar;D:\zookeeper-3.4.6\bin\..\lib\log4j-1.2.16.jar;D:\zookeeper-3.4.6\bin\..\lib\netty-3.7.0.Final.jar;D:\zookeeper-3.4.6\bin\..\lib\slf4j-api-1.6.1.jar;D:\zookeeper-3.4.6\bin\..\lib\slf4j-log4j12-1.6.1.jar;D:\zookeeper-3.4.6\bin\..\conf

2019-03-27 17:05:34,609 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=C:\ProgramData\Oracle\Java\javapath;C:\WINDOWS\Sun\Java\bin;C:\WINDOWS\system32;C:\WINDOWS;D:\Oracle\product\11.2.0\client_2\bin;D:\Oracle\Oracle64;D:\Oracle;C:\ProgramData\Oracle\Java\javapath;C:\Program Files (x86)\Intel\iCLS Client\;C:\Program Files\Intel\iCLS Client\;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem;C:\Windows\System32\WindowsPowerShell\v1.0\;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files\Intel\Intel(R) Management Engine Components\DAL;C:\Program Files (x86)\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files\Intel\Intel(R) Management Engine Components\IPT;C:\Program Files (x86)\NVIDIA Corporation\PhysX\Common;D:\node\;D:\VSCode\bin;d:\eclipse\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\TortoiseSVN\bin;D:\gradle-4.10\bin;D:\gradle-4.10\;D:\node\node_global_modules\;C:\Program Files\Git\bin\;D:\apache-maven-3.5.4\bin;C:\Program Files\NVIDIA Corporation\NVIDIA NvDLISR;;%SystemRoot%\system32;%SystemRoot%;%SystemRoot%\System32\Wbem;%SYSTEMROOT%\System32\WindowsPowerShell\v1.0\;%SYSTEMROOT%\System32\OpenSSH\;C:\Users\nan\AppData\Local\Microsoft\WindowsApps;C:\Users\nan\AppData\Roaming\npm;;.

2019-03-27 17:05:34,610 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=C:\Users\nan\AppData\Local\Temp\

2019-03-27 17:05:34,610 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>

2019-03-27 17:05:34,611 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Windows 8.1

2019-03-27 17:05:34,611 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=amd64

2019-03-27 17:05:34,611 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=6.3

2019-03-27 17:05:34,612 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=nan

2019-03-27 17:05:34,612 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=C:\Users\nan

2019-03-27 17:05:34,621 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=D:\zookeeper-3.4.6

2019-03-27 17:05:34,623 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@277050dc

Welcome to ZooKeeper!

2019-03-27 17:05:34,714 [myid:] - INFO  [main-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@975] - Opening socket connection to server 127.0.0.1/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)

2019-03-27 17:05:34,716 [myid:] - INFO  [main-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@852] - Socket connection established

to 127.0.0.1/127.0.0.1:2181, initiating session

JLine support is enabled

[zk: localhost:2181(CONNECTING) 0] 2019-03-27 17:05:34,856 [myid:] - INFO  [main-SendThread(127.0.0.1:2181):ClientCnxn$SendThread@1235] - Session establishment complete on server 127.0.0.1/127.0.0.1:2181, sessionid = 0x169be6525760000, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null

ls

[zk: localhost:2181(CONNECTED) 1]

创建

通过zkCli连接服务器后，使用```create``可以创建一个ZooKeeper节点，使用方式：

create [-s] [-e] path data acl

-s 顺序节点， -e临时节点，如果补添加创建的就是持久节点

acl是权限控制，缺省情况下，不做任何权限控制

读取

读取指令有两种，ls列出指定节点下的子节点, get获取指定节点的数据内容和属性信息，两个指令的使用方式如下:

ls path [wacth]

get path [watch]

[zk: localhost:2181(CONNECTED) 21] create /test 123

Created /test

[zk: localhost:2181(CONNECTED) 22] ls /test

[]

[zk: localhost:2181(CONNECTED) 23] get /test

123

cZxid = 0x28

ctime = Wed Mar 27 17:42:45 CST 2019

mZxid = 0x28

mtime = Wed Mar 27 17:42:45 CST 2019

pZxid = 0x28

cversion = 0

dataVersion = 0

aclVersion = 0

ephemeralOwner = 0x0

dataLength = 3

numChildren = 0

cZxid创建该节点的事务ID，mZxid最后一次更新该节点的事务ID

更新

set命令用于更新指定节点的数据内容,使用方式如下：

set path data [version]

[zk: localhost:2181(CONNECTED) 24] set /test 111

cZxid = 0x28

ctime = Wed Mar 27 17:42:45 CST 2019

mZxid = 0x29

mtime = Wed Mar 27 17:49:59 CST 2019

pZxid = 0x28

cversion = 0

dataVersion = 1

aclVersion = 0

ephemeralOwner = 0x0

dataLength = 3

numChildren = 0

[zk: localhost:2181(CONNECTED) 25] get /test

111

cZxid = 0x28

ctime = Wed Mar 27 17:42:45 CST 2019

mZxid = 0x29

mtime = Wed Mar 27 17:49:59 CST 2019

pZxid = 0x28

cversion = 0

dataVersion = 1

aclVersion = 0

ephemeralOwner = 0x0

dataLength = 3

numChildren = 0

[zk: localhost:2181(CONNECTED) 26]

执行更新命令后，节点/test的数据已经变成111，````cZxid没有变化，mZxid变成了0x29，dataVersion```从0变成了1。

删除

delete命令用于删除指定节点，使用方式如下:

delete path [version]

删除节点时，该节点不能有子节点。如下：

[zk: localhost:2181(CONNECTED) 27] create /test/test-1 101

Created /test/test-1

[zk: localhost:2181(CONNECTED) 28] ls /test

[test-1]

[zk: localhost:2181(CONNECTED) 29] delete /test

Node not empty: /test

[zk: localhost:2181(CONNECTED) 30] delete /test/test-1

[zk: localhost:2181(CONNECTED) 31] ls

[zk: localhost:2181(CONNECTED) 32] ls /test

[]

[zk: localhost:2181(CONNECTED) 33] delete /test

[zk: localhost:2181(CONNECTED) 34] ls /test

Node does not exist: /test