标签：13 zk zookeeper 2181 CONNECTED 2018 数据结构 节点 localhost
1 zookeeper结构和命令
1.1 zookeeper两大功能：
读写数据：往往是状态信息或配置信息
提供监听：发现数据的变化情况
1.2 zookeeper特性
1、Zookeeper：一个leader，多个follower组成的集群
2、 全局数据一致：每个server保存一份相同的数据副本，client无论连接到哪个server，数据都是一致的
3、分布式读写，更新请求转发，由leader实施
4、更新请求顺序进行，来自同一个client的更新请求按其发送顺序依次执行
5、数据更新原子性，一次数据更新要么成功，要么失败
6、实时性，在一定时间范围内，client能读到最新数据
1.3 zookeeper数据结构
1、层次化的目录结构，命名符合常规文件系统规范(见下图)
2、每个节点在zookeeper中叫做znode,并且其有一个唯一的路径标识
3、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，下一页详细讲解）
4、客户端应用可以在节点上设置监视器（后续详细讲解）
1.4 数据结构图
1.5 读写节点数据:
1.5.1 命令行连接zk服务器
zkCli.sh
返回如下信息：
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[root@min1 ~]# zkCli.sh Connecting to localhost:2181 2018-11-13 07:30:14,084 [myid:] - INFO [main:Environment@100] - Client environment:zookeeper.version=3.4.5-1392090, built on 09/30/2012 17:52 GMT 2018-11-13 07:30:14,094 [myid:] - INFO [main:Environment@100] - Client environment:host.name=min1 2018-11-13 07:30:14,095 [myid:] - INFO [main:Environment@100] - Client environment:java.version=1.7.0_45 2018-11-13 07:30:14,099 [myid:] - INFO [main:Environment@100] - Client environment:java.vendor=Oracle Corporation 2018-11-13 07:30:14,099 [myid:] - INFO [main:Environment@100] - Client environment:java.home=/root/apps/jdk1.7.0_45/jre 2018-11-13 07:30:14,100 [myid:] - INFO [main:Environment@100] - Client environment:java.class.path=/root/apps/zookeeper/bin/../build/classes:/root/apps/zookeeper/bin/../build/lib/*.jar:/root/apps/zookeeper/bin/../lib/slf4j-log4j12-1.6.1.jar:/root/apps/zookeeper/bin/../lib/slf4j-api-1.6.1.jar:/root/apps/zookeeper/bin/../lib/netty-3.2.2.Final.jar:/root/apps/zookeeper/bin/../lib/log4j-1.2.15.jar:/root/apps/zookeeper/bin/../lib/jline-0.9.94.jar:/root/apps/zookeeper/bin/../zookeeper-3.4.5.jar:/root/apps/zookeeper/bin/../src/java/lib/*.jar:/root/apps/zookeeper/bin/../conf: 2018-11-13 07:30:14,100 [myid:] - INFO [main:Environment@100] - Client environment:java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib 2018-11-13 07:30:14,101 [myid:] - INFO [main:Environment@100] - Client environment:java.io.tmpdir=/tmp 2018-11-13 07:30:14,101 [myid:] - INFO [main:Environment@100] - Client environment:java.compiler=<NA> 2018-11-13 07:30:14,102 [myid:] - INFO [main:Environment@100] - Client environment:os.name=Linux 2018-11-13 07:30:14,103 [myid:] - INFO [main:Environment@100] - Client environment:os.arch=amd64 2018-11-13 07:30:14,103 [myid:] - INFO [main:Environment@100] - Client environment:os.version=2.6.32-573.el6.x86_64 2018-11-13 07:30:14,104 [myid:] - INFO [main:Environment@100] - Client environment:user.name=root 2018-11-13 07:30:14,105 [myid:] - INFO [main:Environment@100] - Client environment:user.home=/root 2018-11-13 07:30:14,106 [myid:] - INFO [main:Environment@100] - Client environment:user.dir=/root 2018-11-13 07:30:14,108 [myid:] - INFO [main:ZooKeeper@438] - Initiating client connection, connectString=localhost:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@5cf2baac Welcome to ZooKeeper! 2018-11-13 07:30:14,134 [myid:] - INFO [main-SendThread(localhost:2181):ClientCnxn$SendThread@966] - Opening socket connection to server localhost/127.0.0.1:2181. Will not attempt to authenticate using SASL (unknown error) 2018-11-13 07:30:14,149 [myid:] - INFO [main-SendThread(localhost:2181):ClientCnxn$SendThread@849] - Socket connection established to localhost/127.0.0.1:2181, initiating session JLine support is enabled 2018-11-13 07:30:14,179 [myid:] - INFO [main-SendThread(localhost:2181):ClientCnxn$SendThread@1207] - Session establishment complete on server localhost/127.0.0.1:2181, sessionid = 0x1670a2f4010000a, negotiated timeout = 30000
WATCHER::
WatchedEvent state:SyncConnected type:None path:null [zk: localhost:2181(CONNECTED) 0] |
1.5.2 切换连接的服务器
connect 192.168.33.62:2181 connect min2:2181
返回：
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[zk: localhost:2181(CONNECTED) 1] connect min2:2181 2018-11-13 07:31:44,978 [myid:] - INFO [main-EventThread:ClientCnxn$EventThread@509] - EventThread shut down 2018-11-13 07:31:44,979 [myid:] - INFO [main:ZooKeeper@684] - Session: 0x1670a2f4010000a closed 2018-11-13 07:31:44,985 [myid:] - INFO [main:ZooKeeper@438] - Initiating client connection, connectString=min2:2181 sessionTimeout=30000 watcher=org.apache.zookeeper.ZooKeeperMain$MyWatcher@7bae9cec 2018-11-13 07:31:44,988 [myid:] - INFO [main-SendThread(min2:2181):ClientCnxn$SendThread@966] - Opening socket connection to server min2/192.168.33.62:2181. Will not attempt to authenticate using SASL (unknown error) ZooKeeper -server host:port cmd args connect host:port get path [watch] ls path [watch] set path data [version] rmr path delquota [-n|-b] path quit printwatches on|off create [-s] [-e] path data acl stat path [watch] close ls2 path [watch] history listquota path setAcl path acl getAcl path sync path redo cmdno addauth scheme auth delete path [version] setquota -n|-b val path [zk: min2:2181(CONNECTING) 2] 2018-11-13 07:31:44,990 [myid:] - INFO [main-SendThread(min2:2181):ClientCnxn$SendThread@849] - Socket connection established to min2/192.168.33.62:2181, initiating session 2018-11-13 07:31:44,996 [myid:] - INFO [main-SendThread(min2:2181):ClientCnxn$SendThread@1207] - Session establishment complete on server min2/192.168.33.62:2181, sessionid = 0x2670a2f1b430005, negotiated timeout = 30000
WATCHER::
WatchedEvent state:SyncConnected type:None path:null
[zk: min2:2181(CONNECTED) 2] |
1.5.3 查看节点
ls
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[zk: min2:2181(CONNECTED) 7] ls / [zookeeper]
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1.5.4 创建节点
create /app1 "this is app1 servers parent"
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[zk: min2:2181(CONNECTED) 8] create /app1 "this is app1 servers parent" Created /app1 |
ls
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[zk: min2:2181(CONNECTED) 10] ls / [app1, zookeeper] |
create /app1/server01 "192.168.33.61,100"
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[zk: min2:2181(CONNECTED) 11] create /app1/server01 "192.168.33.61,100" Created /app1/server01 |
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[zk: min2:2181(CONNECTED) 12] ls /app1 [server01] |
1.5.5 获取节点数据
get /app1/server01
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[zk: localhost:2181(CONNECTED) 0] get /app1/server01 "192.168.33.61,100" cZxid = 0x200000023 #内部事务编号 ctime = Tue Nov 13 07:58:10 CST 2018 #创建时间 mZxid = 0x200000023 mtime = Tue Nov 13 07:58:10 CST 2018 #修改时间 pZxid = 0x200000023 #持久化事务 cversion = 0 #创建版本 dataVersion = 0 #数据版本 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 19 #数据长度 numChildren = 0 #子节点数 |
1.5.6 创建一个短暂节点
1.5.6.1 创建短暂节点
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[zk: localhost:2181(CONNECTED) 2] create -e /app-emphemeral 181818 Created /app-emphemeral |
1.5.6.2 查看节点信息
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[zk: localhost:2181(CONNECTED) 4] ls / [app1, app-emphemeral, zookeeper] #可以看到临时节点 |
1.5.6.3 退出后再链接进去查看节点信息
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quit zkCli.sh ls / [zk: localhost:2181(CONNECTED) 0] ls / [app1, zookeeper] #临时节点已经没有了； |
1.5.7 创建带有序号的节点
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[zk: localhost:2181(CONNECTED) 18] create /test 888 Created /test [zk: localhost:2181(CONNECTED) 19] create -s /test/aa 999 Created /test/aa0000000000 |
继续创建
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[zk: localhost:2181(CONNECTED) 20] create -s /test/aa 999 Created /test/aa0000000001 #会自动增加序号添加节点 [zk: localhost:2181(CONNECTED) 21] create -s /test/aa 999 Created /test/aa0000000002 [zk: localhost:2181(CONNECTED) 22] create -s /test/aa 999 Created /test/aa0000000003 [zk: localhost:2181(CONNECTED) 23] create -s /test/aa 999 Created /test/aa0000000004 [zk: localhost:2181(CONNECTED) 24] create -s /test/aa 999 Created /test/aa0000000005 [zk: localhost:2181(CONNECTED) 25] create -s /test/aa 999 Created /test/aa0000000006 [zk: localhost:2181(CONNECTED) 26] create -s /test/aa 999 Created /test/aa0000000007 [zk: localhost:2181(CONNECTED) 27] create -s /test/bb 999 Created /test/bb0000000008 [zk: localhost:2181(CONNECTED) 28] create -s /test/bb 999 Created /test/bb0000000009 [zk: localhost:2181(CONNECTED) 29] create -s /test/cc 999 Created /test/cc0000000010 [zk: localhost:2181(CONNECTED) 30] create -s /test/cc 999 |
创建临时的带序号的节点
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[zk: localhost:2181(CONNECTED) 31] create -e -s /test/cc 999 Created /test/cc0000000012 |
1.5.8 多服务器更新数据同步
61上操作：
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[zk: localhost:2181(CONNECTED) 33] set /app1 111 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000041 mtime = Tue Nov 13 08:41:24 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 1 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 [zk: localhost:2181(CONNECTED) 34] get /app1 111 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000041 mtime = Tue Nov 13 08:41:24 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 1 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 [zk: localhost:2181(CONNECTED) 35] |
登录62，操作：
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zkCli.sh #登录62本机 [zk: localhost:2181(CONNECTED) 0] get /app1 111 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000041 mtime = Tue Nov 13 08:41:24 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 1 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 [zk: localhost:2181(CONNECTED) 1] set /app1 222 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000046 mtime = Tue Nov 13 08:43:54 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 2 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 [zk: localhost:2181(CONNECTED) 2] get /app1 222 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000046 mtime = Tue Nov 13 08:43:54 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 2 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1
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在61上查看
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[zk: localhost:2181(CONNECTED) 0] get /app1 222 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000046 mtime = Tue Nov 13 08:43:54 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 2 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 |
1.6 监听事件
1.6.1 数据变化监听
61上监听：
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[zk: localhost:2181(CONNECTED) 1] get /app1 watch 222 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000046 mtime = Tue Nov 13 08:43:54 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 2 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 [zk: localhost:2181(CONNECTED) 2] WATCHER:: |
62上修改
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[zk: localhost:2181(CONNECTED) 3] set /app1 333 cZxid = 0x200000022 ctime = Tue Nov 13 07:55:17 CST 2018 mZxid = 0x200000048 mtime = Tue Nov 13 08:55:45 CST 2018 pZxid = 0x200000023 cversion = 1 dataVersion = 3 aclVersion = 0 ephemeralOwner = 0x0 dataLength = 3 numChildren = 1 |
在61上发生变化：注意，该事件只接受一次；再修改就不会接受到监听了；
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[zk: localhost:2181(CONNECTED) 2] WATCHER:: WatchedEvent state:SyncConnected type:NodeDataChanged path:/app1 |
1.6.2 子节点变化监听
61上开启节点监听
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[zk: localhost:2181(CONNECTED) 4] ls /app1 watch [server01] |
62上操作，增加节点
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[zk: localhost:2181(CONNECTED) 4] create /app1/app2 222 Created /app1/app2 |
查看61
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[zk: localhost:2181(CONNECTED) 5] WATCHER::
WatchedEvent state:SyncConnected type:NodeChildrenChangedpath:/app1
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[zk: localhost:2181(CONNECTED) 5] ls /app1 [app2, server01] |
1.7 节点类型
1.7.1 Znode有两种类型：
短暂（ephemeral）（断开连接自己删除）
如果创建的客户端断开，那么会被自动删除；
用于服务器掉线的自动感知，掉线后自动删除，那么就知道不存在了；
持久（persistent）（断开连接不删除）
如果创建的客户端断开，那么不会被自动删除；
1.7.2 Znode有四种形式的目录节点（默认是persistent ）
PERSISTENT（持久节点）
PERSISTENT_SEQUENTIAL（持久序列/test0000000019 ）
EPHEMERAL（临时节点）
EPHEMERAL_SEQUENTIAL （临时序列/test0000000019）
创建znode时设置顺序标识，znode名称后会附加一个值，顺序号是一个单调递增的计数器，由父节点维护
在分布式系统中，顺序号可以被用于为所有的事件进行全局排序，这样客户端可以通过顺序号推断事件的顺序
标签：13,zk,zookeeper,2181,CONNECTED,2018,数据结构,节点,localhost 来源： https://www.cnblogs.com/qq18361642/p/11856635.html
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