zookeeper的命令使用

这篇是接着上篇zookeeper集群做的，所以有不熟悉的可以返回看下zookeeper集群的相关内容。

这里是相关的命名行使用方法:

基本命令用法

连接server	zkCli.sh -server Hadoop2:2181	连接到Hadoop2服务器的2181端口
列出指定node的子node	ls /path	查看/path下的子节点列表
创建znode节点, 并指定关联数据	create /data test	创建节点/date, 并将字符串"test"关联到该节点中.
创建临时节点，并关联数据	create -e /data/test lele	在节点/data下创建临时节点test，并将字符串"lele"关联到该节点中。
创建序列节点，并关联数据	create -s /haha/lala	在节点/haha下创建序列节点ilala,以lala为前缀的编号节点，并将字符串关联到该节点中
修改节点的数据	set /data test1	将节点/hello下的值改为test1
获取znode的数据和状态信息	get /test	获取节点/data的数据与状态
获取 znode的数据和状态，并监听	get /test  date	获取节点/hello的数据与状态，并监听其变更
删除znode	delete /date	使用delete命令可以删除指定znode. 当该znode拥有子znode时, 必须先删除其所有子znode, 否则操作将失败. rmr命令可用于代替delete命令, rmr是一个递归删除命令, 如果发生指定节点拥有子节点时, rmr命令会首先删除子节点.

启用znode节点交互界面。

[root@hadoop1 zookeeper]# sh bin/zkCli.sh 
Connecting to localhost:2181
2018-04-19 13:52:53,549 [myid:] - INFO  [main:Environment@100] - Client environment:zookeeper.version=3.4.9-1757313, built on 08/23/2016 06:50 GMT
2018-04-19 13:52:53,553 [myid:] - INFO  [main:Environment@100] - Client environment:host.name=hadoop1
2018-04-19 13:52:53,554 [myid:] - INFO  [main:Environment@100] - Client environment:java.version=1.8.0_152
2018-04-19 13:52:53,556 [myid:] - INFO  [main:Environment@100] - Client environment:java.vendor=Oracle Corporation
2018-04-19 13:52:53,556 [myid:] - INFO  [main:Environment@100] - Client environment:java.home=/usr/local/jdk1.8.0_152/jre
2018-04-19 13:52:53,556 [myid:] - INFO  [main:Environment@100] - Client environment:java.class.path=/data/soft/zookeeper/bin/../build/classes:/data/soft/zookeeper/bin/../build/lib/*.jar:/data/soft/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/data/soft/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/data/soft/zookeeper/bin/../lib/netty-3.10.5.Final.jar:/data/soft/zookeeper/bin/../lib/log4j-1.2.16.jar:/data/soft/zookeeper/bin/../lib/jline-0.9.94.jar:/data/soft/zookeeper/bin/../zookeeper-3.4.9.jar:/data/soft/zookeeper/bin/../src/java/lib/*.jar:/data/soft/zookeeper/bin/../conf:.:/usr/local/jdk1.8.0_152/lib/dt.jar:/usr/local/jdk1.8.0_152/lib/tools.jar
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:java.io.tmpdir=/tmp
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:java.compiler=<NA>
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:os.name=Linux
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:os.arch=amd64
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:os.version=2.6.32-431.el6.x86_64
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:user.name=root
2018-04-19 13:52:53,557 [myid:] - INFO  [main:Environment@100] - Client environment:user.home=/root
2018-04-19 13:52:53,559 [myid:] - INFO  [main:Environment@100] - Client environment:user.dir=/data/soft/zookeeper
2018-04-19 13:52:53,563 [myid:] - INFO  [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@579bb367
Welcome to ZooKeeper!
2018-04-19 13:52:53,611 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1032] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error)
JLine support is enabled
[zk: localhost:2181(CONNECTING) 0] 2018-04-19 13:52:53,795 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@876] - Socket connection established to localhost/127.0.0.1:2181, initiating session
2018-04-19 13:52:53,806 [myid:] - INFO  [main-SendThread(localhost:2181):ClientCnxn$SendThread@1299] - Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x62dc72a43b0001, negotiated timeout = 30000

WATCHER::

WatchedEvent state:SyncConnected type:None path:null

　在交互界面可以看到能够使用的命令

[zk: localhost:2181(CONNECTED) 2] 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

　创建节点/test/　并获取保存节点的信息data

创建节点
[zk: localhost:2181(CONNECTED) 1]  create /test data
Created /test
[zk: localhost:2181(CONNECTED) 2]  ls /
[zookeeper, test]
获取节点信息
[zk: localhost:2181(CONNECTED) 18] get /test
data
cZxid = 0x10000000c   =>节点被创建的zxid值
ctime = Thu Apr 19 13:54:48 CST 2018  =>节点创建的时间
mZxid = 0x10000000c =>节点被修改时zxid值
mtime = Thu Apr 19 13:54:48 CST 2018  =>节点最后一次的修改时间
pZxid = 0x10000000c =>
cversion = 0 => 节点所拥有的子节点被修改的版本号
dataVersion = 0  =>
aclVersion = 0  =>
ephemeralOwner = 0x0  =>
dataLength = 4 =>节点数据的长度
numChildren = 0  =>节点拥有子节点的个数

　　

　在其他节点上看到信息是同步的　

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

[zk: localhost:2181(CONNECTED) 10] get /test
data
cZxid = 0x10000000c
ctime = Thu Apr 19 13:54:48 CST 2018
mZxid = 0x10000000c
mtime = Thu Apr 19 13:54:48 CST 2018
pZxid = 0x10000000c
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 4
numChildren = 0

删除节点delete：但是节点下面不能有子节点

[zk: localhost:2181(CONNECTED) 21] delete /test     
[zk: localhost:2181(CONNECTED) 22] ls /
[zookeeper]

递归删除节点rmr

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

　　

zookeeper的数据模型

层次化的目录结构，命名符合常规文件系统规范

每个节点在zookeeper中叫做znode，并且其有一个唯一的路径标识

节点znode可以包含数据和子节点，但是EPHEMERAL类型的节点不能有子节点

znode中的数据可以有多个版本，比如某一个路径下存有多个数据版本，那么查询这个路径下的数据就需要带上版本

客户端应用可以在节点上设置监视器

节点不支持部分读写，而是一次性完整读写

zookeeper的节点

znode有两种类型，临时节点（ephemeral）和持久节点（persistent）

znode的类型在创建时确定并且之后不能在修改

短暂znode的客户端回话结束时，zookeeper会将该短暂znode删除，短暂znode节点不可以有子节点

持久znode不依赖客户端会话，只有当客户端明确要删除该持久znode时才会被删除

znode有四种形式的目录节点，PERSISTENT、PERSISTENT_SEQUENTIAL、EPHEMERAL、EPHEMERAL_SEQUENTIAL。