zookeeper节点类型

zookeeper的节点类型按照是否持续存在，可分为持久节点和短暂节点，创建命令的区别在于create是否加参数-e

持久节点(Persistent)：客户端和服务器端断开连接后，创建的节点依然存在，不会被不删除

短暂节点(Ephemeral)：客户端和服务器端断开连接后，创建的节点不存在，会被删除，创建时需要加参数-e

[zk: hadoop102:2181(CONNECTED) 0] ls /
[zookeeper]
[zk: hadoop102:2181(CONNECTED) 17] create /wu "zhouyu"
Created /wu
[zk: hadoop102:2181(CONNECTED) 18] create -e  /shu "liubei"
Created /shu
[zk: hadoop102:2181(CONNECTED) 19] ls /
[shu, wu, zookeeper]
[zk: hadoop102:2181(CONNECTED) 20] quit
[root@hadoop102 bin]# ./zkCli.sh -server hadoop102:2181
[zk: hadoop102:2181(CONNECTED) 0] ls /
[wu, zookeeper]

zookeeper的节点类型按照节点名称是否带编号，可分为不带编号的和顺序编号的节点，创建命令的区别在于create是否加参数-s

不带序号的节点：不可重复创建，节点名称唯一

顺序序号的节点：可重复创建，节点名称由父节点顺序编号

[zk: hadoop102:2181(CONNECTED) 15] create /wei "caocao"
Created /wei
[zk: hadoop102:2181(CONNECTED) 16] create /wei "caocao"
Node already exists: /wei
[zk: hadoop102:2181(CONNECTED) 17] create -s /wei "caocao"
Created /wei0000000008
[zk: hadoop102:2181(CONNECTED) 18] create -s /wei "caocao"
Created /wei0000000009
[zk: hadoop102:2181(CONNECTED) 19] ls /
[wei, wei0000000008, wei0000000009, wu, zookeeper]
[zk: hadoop102:2181(CONNECTED) 20] quit
[root@hadoop102 bin]# ./zkCli.sh -server hadoop102:2181
[zk: hadoop102:2181(CONNECTED) 0] ls /
[wei, wei0000000008, wei0000000009, wu, zookeeper]

总结：

创建持久+不带编号的节点：create nodename "nodevalue"

创建持久+带序号的节点：create -s nodename "nodevalue"

创建短暂+不带序号的节点：create -e nodename "nodevalue"

创建短暂+带序号的节点：create -e -s nodename "nodevalue"