zk实践操作
1.入门基础
应用场景
- ZooKeeper主要服务于分布式系统，可以用ZooKeeper来做：统一配置管理、统一命名服务、分布式锁、集群管理。
- 使用分布式系统就无法避免对节点管理的问题(需要实时感知节点的状态、对节点进行统一管理等等)，而由于这些问题处理起来可能相对麻烦和提高了系统的复杂性，ZooKeeper作为一个能够通用解决这些问题的中间件就应运而生了。
从上面我们可以知道，可以用ZooKeeper来做：统一配置管理、统一命名服务、分布式锁、集群管理。
这里我们先不管统一配置管理、统一命名服务、分布式锁、集群管理每个具体的含义(后面会讲)
那为什么ZooKeeper可以干那么多事？来看看ZooKeeper究竟是何方神物，在Wiki中其实也有提到：
ZooKeeper nodes store their data in a hierarchical name space, much like a file system or a tree data structure ZooKeeper的数据结构，跟Unix文件系统非常类似，可以看做是一颗树，每个节点叫做ZNode。
每一个节点可以通过路径来标识，结构图如下：
数据结构
-
zookeeper数据模型的结构，就和linux的文件系统类似，看起来是一棵树，每个节点称作是一个ZNode。
-
每一个ZNode默认存储1MB的数据，每个ZNode都有唯一标识，可以通过命令显示节点的信息。
- 每当节点有数据变化，节点的版本号会累加
- 删除或者修改过时的节点，版本号不匹配的话会报错。
- 每个zk存储的数据不宜过大，一般就几KB
- 每个znode可以设置acl，进行用户的权限访问，不同的节点数据。
那ZooKeeper这颗"树"有什么特点呢？？ZooKeeper的节点我们称之为Znode，Znode分为两种类型：
- 短暂/临时(Ephemeral)：当客户端和服务端断开连接后，所创建的Znode(节点)会自动删除
- 持久(Persistent)：当客户端和服务端断开连接后，所创建的Znode(节点)不会删除
ZooKeeper和Redis一样，也是C/S结构(分成客户端和服务端)
监听器
在上面我们已经简单知道了ZooKeeper的数据结构了，ZooKeeper还配合了监听器才能够做那么多事的。
常见的监听场景有以下两项：
- 监听Znode节点的数据变化
- 监听子节点的增减变化，/app1节点，以及子节点是否有增减
ZooKeeper强大的功能
下面我们来看看用ZooKeeper怎么来做：统一配置管理、统一命名服务、分布式锁、集群管理。
统一配置管理
比如我们现在有三个系统A、B、C，他们有三份配置，分别是ASystem.yml、BSystem.yml、CSystem.yml，然后，这三份配置又非常类似，很多的配置项几乎都一样。
- 此时，如果我们要改变其中一份配置项的信息，很可能其他两份都要改。并且，改变了配置项的信息很可能就要重启系统
于是，我们希望把ASystem.yml、BSystem.yml、CSystem.yml相同的配置项抽取出来成一份公用的配置common.yml，并且即便common.yml改了，也不需要系统A、B、C重启。
做法：我们可以将common.yml这份配置放在ZooKeeper的Znode节点中，系统A、B、C监听着这个Znode节点有无变更，如果变更了，及时响应。
统一命名服务
统一命名服务的理解其实跟域名一样，是我们为这某一部分的资源给它取一个名字，别人通过这个名字就可以拿到对应的资源。
比如说，现在我有一个域名www.yuchaoit.cn，但我这个域名下有多台机器：
- 192.168.1.1
- 192.168.1.2
- 192.168.1.3
- 192.168.1.4
别人访问www.yuchaoit.cn即可访问到我的机器，而不是通过IP去访问。
分布式锁
java开发需要了解的内容，暂时先略过。
分布式锁，是指多进程下对数据课程产生的资源抢夺。
由于锁的存在就保证了数据的依次操作，锁释放后其他人才能干活。
发布订阅
动态上下线
1.系统启动时，去zk注册信息，创建临时节点
2.zk获取到在线服务器的列表，且监听
3.zk若某节点下线，服务器也会通知其他节点该事件。
4.客户单
经过上面几个例子，我相信大家也很容易想到ZooKeeper是怎么"感知"节点的动态新增或者删除的了。
只要系统A挂了，那么对应的znode就会被删除，只要监听/cluster子节点的变化，就可以感知系统的故障，同时也告知B、C系统，A系统挂了。
类似于MQ，kafka，rabbitmq的功能
数据存储在znode上，订阅者会读取这个数据。
zk集群中的角色
像Mysql的主从模式会分master主节点和slave从节点一样，在zookeeper集群中，节点也有不同的角色，承担着不同角色。
zookeeper有三种角色：老大Leader(领导者） 2、老二Follower （跟随者） 3、老三Observer（观察者）。其中，Follower和Observer归类为Learner（学习者）
按重要性排序是Leader > Follower > Observer
老大领导者Leader。
Leader在集群中只有一个节点，可以说是老大No.1，是zookeeper集群的中心，负责协调集群中的其他节点。从性能的角度考虑，leader可以选择不接受客户端的连接。
主要作用有：
1、发起与提交写请求。
所有的跟随者Follower与观察者Observer节点的写请求都会转交给领导者Leader执行。Leader接受到一个写请求后，首先会发送给所有的Follower，统计Follower写入成功的数量。当有超过半数的Follower写入成功后，Leader就会认为这个写请求提交成功，通知所有的Follower commit这个写操作，保证事后哪怕是集群崩溃恢复或者重启，这个写操作也不会丢失。
2、与learner保持心跳
3、崩溃恢复时负责恢复数据以及同步数据到Learner
老二跟随者Follower。
Follow在集群中有多个，主要的作用有：
1、与老大Leader保持心跳连接
2、当Leader挂了的时候，经过投票后成为新的leader。leader的重新选举是由老二Follower们内部投票决定的。
3、向leader发送消息与请求
4、处理leader发来的消息与请求
老三观察者Observer
可以说Observer是zookeeper集群中最边缘的存在。Observer的主要作用是提高zookeeper集群的读性能。通过leader的介绍我们知道zookeeper的一个写操作是要经过半数以上的Follower确认才能够写成功的。那么当zookeeper集群中的节点越多时，zookeeper的写性能就 越差。为了在提高zookeeper读性能（也就是支持更多的客户端连接）的同时又不影响zookeeper的写性能，zookeeper集群多了一个儿子Observer，只负责：
1、与leader同步数据
2、不参与leader选举，没有投票权。也不参与写操作的提议过程。
3、数据没有事务化到硬盘。即Observer只会把数据加载到内存。
2.安装部署
# 查看zk运行状态
[root@localhost bin]# /opt/zookeeper/bin/zkServer.sh status
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Mode: standalone
[root@localhost bin]#
[root@localhost bin]# jps -l
12322 org.apache.zookeeper.server.quorum.QuorumPeerMain
73240 sun.tools.jps.Jps
[root@localhost bin]#
# 脚本客户端命令
[root@localhost bin]# pwd
/opt/zookeeper/bin
[root@localhost bin]# ./zkCli.sh
# zoo.cfg配置文件
[root@localhost conf]# grep '^[a-z]' zoo.cfg
tickTime=2000 # zk服务器和客户端通信，心跳时间，毫秒
initLimit=10 # leader > follower 初始连接时，能容忍的tickTIme的数量，也就是总时间
syncLimit=5 # leader > follower 之间通信时间，如果超过 syncLimit * tickTime，Leader认为F挂了
dataDir=/opt/zookeeper/zkdata # 数据目录
clientPort=2181 # 客户端连接端口
[root@localhost conf]#3.zk集群安装
1. 三台机器，都准备好zk
[root@devops01 /opt]#java -version
java version "1.8.0_181"
Java(TM) SE Runtime Environment (build 1.8.0_181-b13)
Java HotSpot(TM) 64-Bit Server VM (build 25.181-b13, mixed mode)
2.
tar -zxf apache-zookeeper-3.5.6-bin.tar.gz
ln -s /opt/apache-zookeeper-3.5.6-bin/ /opt/zookeeper
3.修改配置启动，且修改zk机器的id号，三台机器都要执行
mkdir -p /opt/zookeeper/zkData
cd /opt/zookeeper/conf
cp zoo_sample.cfg zoo.cfg
sed -i '/dataDir=/c dataDir=/opt/zookeeper/zkData' zoo.cfg
4. 创建服务器编号文件，得在数据目录下，zk源码要求文件名是myid，机器区别开就好。
就是每个机器的唯一标识
cd /opt/zookeeper/zkData
echo '1' > myid
echo '2' > myid
echo '3' > myid
# 检查
ls /opt/zookeeper/zkData
5.继续修改zoo.cfg配置文件，添加集群信息
# 固定语法格式：server.节点ID=ip:数据同步端口:选举端口
# 节点ID：服务id手动指定1至125之间的数字，并写到对应服务节点的 {dataDir}/myid 文件中。
# IP地址：节点的远程IP地址
# 数据同步端口：主从同步数据复制端口，follower和leader交换数据
# 远举端口：主节点挂了，选举新的主节点的通信端口。leader挂了需要选举新的主节点，通信端口。
# tail -3 zoo.cfg
server.1=10.0.0.18:2888:3888
server.2=10.0.0.19:2888:3888
server.3=10.0.0.20:2888:3888
6.启动zk集群
/opt/zookeeper/bin/zkServer.sh start
/opt/zookeeper/bin/zkServer.sh status
4.zk选举机制
初始化选举
1. 服务器A启动、发起选举，只有单机因此投自己一票，但是机器数量不达最少的3台，选举无法继续，服务器A状态为looking
2. 服务器B启动，发起选举，根据myid越大，作为leader，因此服务器B两票，服务器A零票，但依然未达到最少的3台，依然looking
3.服务器C启动，发起选举，myid最大是3，因此最后选票是，服务器C三票。
此时服务器C是leading、其他机器是following
4.又加入新zk节点，发起选举，其他节点并非looking状态，不会再改票，因此还以服务器C位leader
每台zk机器，都有sid，也就是服务器唯一标识id号，同于myid。
5.节点管理
启停管理
做好免密
yum install sshpass -y
echo "正在创建公私钥..."
if [ -f /root/.ssh/id_rsa ]
then
echo "密钥对已经存在,请检查！"
else
ssh-keygen -f /root/.ssh/id_rsa -N '' > /tmp/create_ssh.log 2>&1
fi
#2.管理机自动分发公钥到备管理机
echo "正在分发公钥中...分发的机器列表是{18,19,20}"
for ip in {18,19,20}
do
sshpass -p '123123' ssh-copy-id 10.0.0.${ip} -o StrictHostKeyChecking=no > /tmp/create_ssh.log 2>&1
echo "正在验证免密登录结果中...."
echo "远程获取到主机名: $(ssh 10.0.0.${ip} hostname)"
done管理脚本
#!/bin/bash
# author: www.yuchaoit.cn
case $1 in
"start"){
for i in {18,19,20}
do
echo "--zk 10.0.0.$i 启动中..."
ssh 10.0.0.$i "/opt/zookeeper/bin/zkServer.sh start"
echo
echo
done
}
;;
"stop"){
for i in {18,19,20}
do
echo "--zk 10.0.0.$i 关闭中..."
ssh 10.0.0.$i "/opt/zookeeper/bin/zkServer.sh stop"
echo
echo
done
}
;;
"status"){
for i in {18,19,20}
do
echo "--zk 10.0.0.$i 状态查看---"
ssh 10.0.0.$i "/opt/zookeeper/bin/zkServer.sh status"
echo
echo
done
}
;;
esac客户端操作
# 连接指定zk服务器
[root@devops01 ~]#/opt/zookeeper/bin/zkCli.sh -server 10.0.0.19:2181
# help查看命令帮助
[zk: 10.0.0.19:2181(CONNECTED) 1] ls / # 查看路径
[zookeeper]
[zk: 10.0.0.19:2181(CONNECTED) 2]
[zk: 10.0.0.19:2181(CONNECTED) 2] ls -s /
[zookeeper]cZxid = 0x0 # 创建节点时的一个事务id
ctime = Thu Jan 01 08:00:00 CST 1970 # 创建节点的时间，
mZxid = 0x0 # 最后更新的事务
mtime = Thu Jan 01 08:00:00 CST 1970 # 最后一次修改节点的时间
pZxid = 0x0 # 最后更新的子节点事务id
cversion = -1 # 子节点变化的次数
dataVersion = 0 # 节点变化号
aclVersion = 0 # 节点访问控制变化号
ephemeralOwner = 0x0 # 如果是临时节点，就是session id ，非临时节点就是0
dataLength = 0
numChildren = 1
[zk: 10.0.0.19:2181(CONNECTED) 3]
# 链接本地zk服务端，已连接
WATCHER::
WatchedEvent state:SyncConnected type:None path:null
[zk: localhost:2181(CONNECTED) 0]
# 基础环境，没有任何数据
[zk: localhost:2181(CONNECTED) 0] ls /
[zookeeper]
[zk: localhost:2181(CONNECTED) 1]
[zk: localhost:2181(CONNECTED) 1] ls /zookeeper
[config, quota]
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] ls /zookeeper/quota
[]
[zk: localhost:2181(CONNECTED) 3]
[zk: localhost:2181(CONNECTED) 3] ls /zookeeper/config
[]
[zk: localhost:2181(CONNECTED) 4]znode管理命令
# 查看znode的状态信息
[zk: localhost:2181(CONNECTED) 2] ls -s /
[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
[zk: localhost:2181(CONNECTED) 3]
# stat 等同于 ls -s
[zk: localhost:2181(CONNECTED) 3] stat /
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
[zk: localhost:2181(CONNECTED) 4]
# 获取znode数据，默认空
[zk: localhost:2181(CONNECTED) 6] get /
[zk: localhost:2181(CONNECTED) 7]create
# 创建节点，默认是持久化的
[zk: localhost:2181(CONNECTED) 8]
[zk: localhost:2181(CONNECTED) 8] create /chaoge linux666
Created /chaoge
[zk: localhost:2181(CONNECTED) 9] ls
ls [-s] [-w] [-R] path
[zk: localhost:2181(CONNECTED) 10] ls /
[chaoge, zookeeper]
# 查看节点数据
[zk: localhost:2181(CONNECTED) 12] get /chaoge
linux666
[zk: localhost:2181(CONNECTED) 13]
# 查看节点状态
[zk: localhost:2181(CONNECTED) 13] stat /chaoge
cZxid = 0x200000008
ctime = Fri Nov 11 00:23:17 CST 2022
mZxid = 0x200000008
mtime = Fri Nov 11 00:23:17 CST 2022
pZxid = 0x200000008
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 0
# 创建临时节点
[zk: localhost:2181(CONNECTED) 14] create -e /chaoge/test test666
Created /chaoge/test
[zk: localhost:2181(CONNECTED) 15] stat /chaoge
cZxid = 0x200000008
ctime = Fri Nov 11 00:23:17 CST 2022
mZxid = 0x200000008
mtime = Fri Nov 11 00:23:17 CST 2022
pZxid = 0x200000009
cversion = 1 # 子节点有更新，版本号+1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 1
[zk: localhost:2181(CONNECTED) 16]
# 查看临时节点
[zk: localhost:2181(CONNECTED) 16] stat /chaoge/test
cZxid = 0x200000009
ctime = Fri Nov 11 00:24:58 CST 2022
mZxid = 0x200000009
mtime = Fri Nov 11 00:24:58 CST 2022
pZxid = 0x200000009
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x10005fdea010001 # 表示是临时节点，十六进制数值
dataLength = 7
numChildren = 0
[zk: localhost:2181(CONNECTED) 17]
# 断开客户端，server的链接，重新连接，临时节点会被删除（有一定的等待时间）
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0] ls /
[chaoge, zookeeper]
[zk: localhost:2181(CONNECTED) 1] ls /chaoge
[] # 临时节点被删除了
[zk: localhost:2181(CONNECTED) 2]
# 创建顺序节点，用参数-s，递增添加序号，并且是持久化的节点，以及数据
[zk: localhost:2181(CONNECTED) 2] create
create [-s] [-e] [-c] [-t ttl] path [data] [acl]
[zk: localhost:2181(CONNECTED) 3]
[zk: localhost:2181(CONNECTED) 3] create -s /chaoge/test test666
Created /chaoge/test0000000001
[zk: localhost:2181(CONNECTED) 4] create -s /chaoge/test test666
Created /chaoge/test0000000002
[zk: localhost:2181(CONNECTED) 5] create -s /chaoge/test test666
Created /chaoge/test0000000003
[zk: localhost:2181(CONNECTED) 6] create -s /chaoge/test test666
Created /chaoge/test0000000004
[zk: localhost:2181(CONNECTED) 7] ls /chaoge
[test0000000001, test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 8] get /chaoge/test000000000
test0000000001 test0000000002 test0000000003 test0000000004
[zk: localhost:2181(CONNECTED) 8] get /chaoge/test0000000001
test666
[zk: localhost:2181(CONNECTED) 9]set
修改znode数据
[zk: localhost:2181(CONNECTED) 6] stat /chaoge
cZxid = 0x200000008
ctime = Fri Nov 11 00:23:17 CST 2022
mZxid = 0x200000008
mtime = Fri Nov 11 00:23:17 CST 2022
pZxid = 0x20000000f
cversion = 6
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 4
[zk: localhost:2181(CONNECTED) 7]
[zk: localhost:2181(CONNECTED) 7]
[zk: localhost:2181(CONNECTED) 7] get /chaoge
linux666
[zk: localhost:2181(CONNECTED) 8]
[zk: localhost:2181(CONNECTED) 8] set /chaoge linux777
[zk: localhost:2181(CONNECTED) 9] get /chaoge
linux777
[zk: localhost:2181(CONNECTED) 10] stat /chaoge
cZxid = 0x200000008
ctime = Fri Nov 11 00:23:17 CST 2022
mZxid = 0x200000012
mtime = Fri Nov 11 01:45:11 CST 2022
pZxid = 0x20000000f
cversion = 6
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 4
[zk: localhost:2181(CONNECTED) 11] set /chaoge linux888
[zk: localhost:2181(CONNECTED) 12] stat /chaoge
cZxid = 0x200000008
ctime = Fri Nov 11 00:23:17 CST 2022
mZxid = 0x200000013
mtime = Fri Nov 11 01:45:23 CST 2022
pZxid = 0x20000000f
cversion = 6
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 8
numChildren = 4
[zk: localhost:2181(CONNECTED) 13]
# 每次修改，版本号会变化，累加delete
[zk: localhost:2181(CONNECTED) 1] delete /chaoge/test0000000001
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] ls /chaoge
[test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 3]watcher机制
1. 每个节点的操作，都会被一个watcher 监督
2. 某个znode变化，触发watcher事件
3. zk中的watcher是一次性，触发后就被销毁
4. 父节点、子节点的修改操作，都引发watcher，并且不同类型的操作，watcher事件也不同。父节点 -w 事件
- 创建父节点，触发NodeCreated
- 创建父节点数据，触发NodeDataChanged
- 删除父节点，触发，NodeDeleted
[zk: localhost:2181(CONNECTED) 2] stat -w /yu
cZxid = 0x20000001b
ctime = Fri Nov 11 02:24:38 CST 2022
mZxid = 0x200000020
mtime = Fri Nov 11 02:26:01 CST 2022
pZxid = 0x20000001b
cversion = 0
dataVersion = 2
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 3
numChildren = 0
# 事件类型，NodeDataChanged
[zk: localhost:2181(CONNECTED) 3] set /yu 777
WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/yu
[zk: localhost:2181(CONNECTED) 4]
# 注意不要忘了，watcher事件是一次性的
# 本次没有watcher了
[zk: localhost:2181(CONNECTED) 4] delete /yu
[zk: localhost:2181(CONNECTED) 5]
# 因此你要提前先加事件 -w
[zk: localhost:2181(CONNECTED) 6] create /yu 666
Created /yu
[zk: localhost:2181(CONNECTED) 7] get -w /yu
666
[zk: localhost:2181(CONNECTED) 8] delete /yu
WATCHER::
WatchedEvent state:SyncConnected type:NodeDeleted path:/yu
[zk: localhost:2181(CONNECTED) 9]子节点事件
- 父节点设置watcher，创建子节点，触发NodeChildrenChanged
- 父节点设置watcher，删除子节点，触发NodeChildrenChanged
- 父节点设置watcher，修改子节点，无事件
[zk: localhost:2181(CONNECTED) 9] ls /chaoge
[test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 10]
[zk: localhost:2181(CONNECTED) 10]
[zk: localhost:2181(CONNECTED) 10] ls -w /chaoge
[test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 11]
[zk: localhost:2181(CONNECTED) 11] create /chaoge/t1
Created /chaoge/t1
WATCHER::
# 子节点修改事件
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/chaoge
[zk: localhost:2181(CONNECTED) 12]
[zk: localhost:2181(CONNECTED) 12] create /chaoge/t2
Created /chaoge/t2
[zk: localhost:2181(CONNECTED) 13] ls /chaoge
[t1, t2, test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 14]
# 删除事件，子节点的删除，对应的事件，和父节点关系而言，都只是修改而已
[zk: localhost:2181(CONNECTED) 14] ls -w /chaoge
[t1, t2, test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 15]
[zk: localhost:2181(CONNECTED) 15] delete /chaoge/t2
WATCHER::
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/chaoge
[zk: localhost:2181(CONNECTED) 16]
[zk: localhost:2181(CONNECTED) 16]
[zk: localhost:2181(CONNECTED) 16] ls -w /chaoge
[t1, test0000000002, test0000000003, test0000000004]
[zk: localhost:2181(CONNECTED) 17]
[zk: localhost:2181(CONNECTED) 17] set /chaoge/t1 999
[zk: localhost:2181(CONNECTED) 18]
# 想看到子节点的事件，得看你watcher的是什么节点
[zk: localhost:2181(CONNECTED) 20] get -w /chaoge/t1
999
[zk: localhost:2181(CONNECTED) 21] set /chaoge/t1 777
WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/chaoge/t1
[zk: localhost:2181(CONNECTED) 22]watcher使用场景
6.ACL权限控制
access control lists 权限控制
1. 针对znode设置读写权限，保障数据安全
2. 权限可以指定不同的范围，以及角色理解scheme
理解permissions
create 创建子节点
read 获取节点、子节点
write 设置节点数据
delete 删除子节点
admin 管理员权限
缩写cdrwa 权限组合ACL命令
getAcl 获取某znode的acl权限
setAcl 设置某znode的acl权限
addauth 输入认证授权信息，注册时输入明文密码，zk写入加密后的数据getAcl
[zk: localhost:2181(CONNECTED) 23] getAcl /chaoge
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 24]
所有的人，所有匿名用户，都可以最大化权限操作
可以看到，默认这个/chaoge节点，是公开访问的，权限是 cdrwa也就是，允许所有权限setAcl
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0] getAcl /chaoge/t1
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 1]
# 修改节点权限
[zk: localhost:2181(CONNECTED) 1] setAcl /chaoge/t1 world:anyone:crwa
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] getAcl /chaoge/t1
'world,'anyone
: crwa
[zk: localhost:2181(CONNECTED) 3]
# 注意父子节点的关系，若是要测试删除，delete权限的话，若是父节点，有d权限，就是可以删除子节点的。
[zk: localhost:2181(CONNECTED) 4] getAcl /chaoge
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 5]
[zk: localhost:2181(CONNECTED) 5] getAcl /chaoge/t1
'world,'anyone
: crwa
[zk: localhost:2181(CONNECTED) 6]
[zk: localhost:2181(CONNECTED) 6] getAcl /chaoge/t1/tt1
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 7]
[zk: localhost:2181(CONNECTED) 7] delete /chaoge/t1/tt1
Authentication is not valid : /chaoge/t1/tt1
[zk: localhost:2181(CONNECTED) 8]
添加可删除的权限
[zk: localhost:2181(CONNECTED) 8] setAcl /chaoge/t1 world:anyone:rda
[zk: localhost:2181(CONNECTED) 9]
[zk: localhost:2181(CONNECTED) 9] getAcl /chaoge/t1
'world,'anyone
: dra
[zk: localhost:2181(CONNECTED) 10]
[zk: localhost:2181(CONNECTED) 10] delete /chaoge/t1/tt1
[zk: localhost:2181(CONNECTED) 11]
[zk: localhost:2181(CONNECTED) 11] ls /chaoge/t1
[]
[zk: localhost:2181(CONNECTED) 12]
# t1节点是可以dra权限的，注意，a权限别乱动，否则无法操作了。world权限类型实践
[zk: localhost:2181(CONNECTED) 12] setAcl /chaoge/t1 world:anyone:a
[zk: localhost:2181(CONNECTED) 13]
[zk: localhost:2181(CONNECTED) 13]
[zk: localhost:2181(CONNECTED) 13] getAcl /chaoge/t1
'world,'anyone
: a
[zk: localhost:2181(CONNECTED) 14]
[zk: localhost:2181(CONNECTED) 14] get /chaoge/t1
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /chaoge/t1
[zk: localhost:2181(CONNECTED) 15]
[zk: localhost:2181(CONNECTED) 15]
[zk: localhost:2181(CONNECTED) 15] set /chaoge/t1 111
Authentication is not valid : /chaoge/t1
[zk: localhost:2181(CONNECTED) 16]
# 重新给权限，给写入的权限
[zk: localhost:2181(CONNECTED) 16] setAcl /chaoge/t1 world:anyone:aw
[zk: localhost:2181(CONNECTED) 17]
[zk: localhost:2181(CONNECTED) 17] getAcl /chaoge/t1
'world,'anyone
: wa
[zk: localhost:2181(CONNECTED) 18] set /chaoge/t1 111
[zk: localhost:2181(CONNECTED) 19] get /chaoge/t1
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /chaoge/t1
[zk: localhost:2181(CONNECTED) 20]
# 还需要给读取权限
[zk: localhost:2181(CONNECTED) 20] setAcl /chaoge/t1 world:anyone:rwa
[zk: localhost:2181(CONNECTED) 21]
[zk: localhost:2181(CONNECTED) 21]
[zk: localhost:2181(CONNECTED) 21] getAcl /chaoge/t1
'world,'anyone
: rwa
[zk: localhost:2181(CONNECTED) 22]
# 可以读取数据了
[zk: localhost:2181(CONNECTED) 23] get /chaoge/t1
111
[zk: localhost:2181(CONNECTED) 24]
[zk: localhost:2181(CONNECTED) 24]Auth类型实践
[zk: localhost:2181(CONNECTED) 25]
[zk: localhost:2181(CONNECTED) 25] create /names
Created /names
[zk: localhost:2181(CONNECTED) 26] ls /
[chaoge, names, zookeeper]
[zk: localhost:2181(CONNECTED) 27] get /names
null
[zk: localhost:2181(CONNECTED) 28]
[zk: localhost:2181(CONNECTED) 28] getAcl /names
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 29]
[zk: localhost:2181(CONNECTED) 29] create /names/yu 666
Created /names/yu
[zk: localhost:2181(CONNECTED) 30]
# 需要先注册用户，等于登录账号密码
[zk: localhost:2181(CONNECTED) 30] addauth digest yuchao:chaoge666
[zk: localhost:2181(CONNECTED) 31]
# 密码是加密显示的
# 首次给znode设置账密之后，后续的处理，就是以改用户的认证操作了
# 给znode设置对应的账密
[zk: localhost:2181(CONNECTED) 32] setAcl /names/yu auth:yuchao:chaoge666:cdrwa
[zk: localhost:2181(CONNECTED) 33]
[zk: localhost:2181(CONNECTED) 33] getAcl /names/yu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdrwa
[zk: localhost:2181(CONNECTED) 34]
[zk: localhost:2181(CONNECTED) 32] setAcl /names/yu auth:yuchao:chaoge666:cdrwa
[zk: localhost:2181(CONNECTED) 33]
[zk: localhost:2181(CONNECTED) 33] getAcl /names/yu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdrwa
[zk: localhost:2181(CONNECTED) 34]
[zk: localhost:2181(CONNECTED) 34] get /names/yu
666
[zk: localhost:2181(CONNECTED) 35] setAcl /names/yu auth::cdrwa
[zk: localhost:2181(CONNECTED) 36] getAcl /names/yu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdrwa
# 即使再填入账号密码，也无用，以第一次的auth账密为准
[zk: localhost:2181(CONNECTED) 37] setAcl /names/yu auth:xxx:xxx:cdrwa
[zk: localhost:2181(CONNECTED) 38] getAcl /names/yu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdrwa
[zk: localhost:2181(CONNECTED) 39]
[zk: localhost:2181(CONNECTED) 39] set /names/yu 777
[zk: localhost:2181(CONNECTED) 40]
[zk: localhost:2181(CONNECTED) 41] get /names/yu
777
[zk: localhost:2181(CONNECTED) 42] getAcl /names/yu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdrwa
[zk: localhost:2181(CONNECTED) 43]
# 重新登录的话，需要再次用户验证
# author www.yuchaoit.cn
需要先退出当前用户
quit
重新登录后，发现访问节点无权限了
[zk: localhost:2181(CONNECTED) 0] get /names/yu
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /names/yu
[zk: localhost:2181(CONNECTED) 1]
[zk: localhost:2181(CONNECTED) 12] addauth digest yuchao:chaoge666
[zk: localhost:2181(CONNECTED) 13] get /names/yu
777
[zk: localhost:2181(CONNECTED) 14]digest类型测试
需要先退出当前用户
quit
重新登录后，发现访问节点无权限了
[zk: localhost:2181(CONNECTED) 0] get /names/yu
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /names/yu
[zk: localhost:2181(CONNECTED) 1]
[zk: localhost:2181(CONNECTED) 12] addauth digest yuchao:chaoge666
[zk: localhost:2181(CONNECTED) 13] get /names/yu
777
[zk: localhost:2181(CONNECTED) 14]
确保重新登录
[zk: localhost:2181(CONNECTED) 0] create /names/yuyu 666
Created /names/yuyu
[zk: localhost:2181(CONNECTED) 1] get /names/yuyu
666
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] getAcl /names/yuyu
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 3]
给znode设置账密，直接设置加密后的密码，别明文设置
[zk: localhost:2181(CONNECTED) 4] setAcl /names/yuyu digest:yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=:cdra
[zk: localhost:2181(CONNECTED) 5]
需要登录，才能访问了
[zk: localhost:2181(CONNECTED) 5] getAcl /names/yuyu
Authentication is not valid : /names/yuyu
[zk: localhost:2181(CONNECTED) 6]
[zk: localhost:2181(CONNECTED) 6] get /names/yuyu
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /names/yuyu
[zk: localhost:2181(CONNECTED) 7]
登录还是等用明文，就好
[zk: localhost:2181(CONNECTED) 7]
[zk: localhost:2181(CONNECTED) 7] addauth digest yuchao:chaoge666
[zk: localhost:2181(CONNECTED) 8]
[zk: localhost:2181(CONNECTED) 8] get /names/yuyu
666
[zk: localhost:2181(CONNECTED) 9] getAcl /names/yuyu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdra
[zk: localhost:2181(CONNECTED) 10]
测试读写
[zk: localhost:2181(CONNECTED) 9] getAcl /names/yuyu
'digest,'yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=
: cdra
[zk: localhost:2181(CONNECTED) 10]
[zk: localhost:2181(CONNECTED) 10] set /names/yuyu 777 # 无w权限
Authentication is not valid : /names/yuyu
[zk: localhost:2181(CONNECTED) 11]
[zk: localhost:2181(CONNECTED) 11] delete /names/yuyu
[zk: localhost:2181(CONNECTED) 12]
[zk: localhost:2181(CONNECTED) 12] get /names/yuyu
org.apache.zookeeper.KeeperException$NoNodeException: KeeperErrorCode = NoNode for /names/yuyu
[zk: localhost:2181(CONNECTED) 13]
[zk: localhost:2181(CONNECTED) 13] ls /names
[yu]
[zk: localhost:2181(CONNECTED) 14]ip类型验证
该功能用于限制客户端访问
重新登录后
[zk: localhost:2181(CONNECTED) 0]
[zk: localhost:2181(CONNECTED) 0] create /names/ip ip666
Created /names/ip
[zk: localhost:2181(CONNECTED) 1]
[zk: localhost:2181(CONNECTED) 1] getAcl /names/ip
'world,'anyone
: cdrwa
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] setAcl /names/ip ip:10.0.0.1:cdrwa
[zk: localhost:2181(CONNECTED) 3] getAcl /names/ip
Authentication is not valid : /names/ip
[zk: localhost:2181(CONNECTED) 4]
[zk: localhost:2181(CONNECTED) 4]
[zk: localhost:2181(CONNECTED) 4]
然后还得用代码客户端测试，才能演示ip效果。super超级用户
当你忘记普通用户的密码，无权限操作znode时咋办，需要超级用户了。
1. 修改zkServer.sh 添加super管理员
nohup "$JAVA" $ZOO_DATADIR_AUTOCREATE "-Dzookeeper.log.dir=${ZOO_LOG_DIR}" \
"-Dzookeeper.DigestAuthenticationProvider.superDigest=yuchao:fGk68NJLSXUaVJQTDztOdxFRv7g=" \
"-Dzookeeper.log.file=${ZOO_LOG_FILE}" "-Dzookeeper.root.logger=${ZOO_LOG4J_PROP}" \
-XX:+HeapDumpOnOutOfMemoryError -XX:OnOutOfMemoryError='kill -9 %p' \
-cp "$CLASSPATH" $JVMFLAGS $ZOOMAIN "$ZOOCFG" > "$_ZOO_DAEMON_OUT" 2>&1 < /dev/null &
2. 重启zk
[root@devops01 /opt/zookeeper/bin]#
[root@devops01 /opt/zookeeper/bin]#
[root@devops01 /opt/zookeeper/bin]#./zkServer.sh restart
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@devops01 /opt/zookeeper/bin]#
3.客户端操作，再次登录
[zk: localhost:2181(CONNECTED) 0] ls /names
[ip, yu]
[zk: localhost:2181(CONNECTED) 1] ls /names/ip
Authentication is not valid : /names/ip
[zk: localhost:2181(CONNECTED) 2]
[zk: localhost:2181(CONNECTED) 2] get /names/ip
org.apache.zookeeper.KeeperException$NoAuthException: KeeperErrorCode = NoAuth for /names/ip
[zk: localhost:2181(CONNECTED) 3]
[zk: localhost:2181(CONNECTED) 3] getAcl /names/ip
Authentication is not valid : /names/ip
[zk: localhost:2181(CONNECTED) 4]
[zk: localhost:2181(CONNECTED) 4]
4.登录超级用户，有权限了
[zk: localhost:2181(CONNECTED) 4] addauth digest yuchao:chaoge666
[zk: localhost:2181(CONNECTED) 5]
[zk: localhost:2181(CONNECTED) 5] getAcl /names/ip
'ip,'10.0.0.1
: cdrwa
[zk: localhost:2181(CONNECTED) 6]
[zk: localhost:2181(CONNECTED) 6] get /names/ip
ip666
[zk: localhost:2181(CONNECTED) 7]
acl使用场景
1. 基于acl实现、开发、测试环境分离，互相无权限操作对应节点，只能读取。
2. 生产下限制可访问的ip7.zk四字命令
1. zk提供了一些简单命令，和服务端交互
2. 用nc命令测试 yum install nc -y
3. 要修改zoo.cfg配置文件
[root@devops01 /opt/zookeeper]#tail -1 ./conf/zoo.cfg
4lw.commands.whitelist=stat, ruok, conf, isro,dump,cons ,envi
[root@devops01 /opt/zookeeper]#
4.重启
[root@devops01 /opt/zookeeper]#./bin/zkServer.sh restart
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
Stopping zookeeper ... STOPPED
/usr/bin/java
ZooKeeper JMX enabled by default
Using config: /opt/zookeeper/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[root@devops01 /opt/zookeeper]#
参考资料
https://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
3. 官网
https://zookeeper.apache.org/doc/r3.4.13/zookeeperAdmin.html#sc_zkCommands
4.stat命令，查看zk状态信息
[root@devops01 /opt/zookeeper]#echo stat | nc 10.0.0.18 2181
Zookeeper version: 3.5.6-c11b7e26bc554b8523dc929761dd28808913f091, built on 10/08/2019 20:18 GMT
Clients:
/10.0.0.18:43450[0](queued=0,recved=1,sent=0)
Latency min/avg/max: 0/0/0
Received: 1
Sent: 0
Connections: 1
Outstanding: 0
Zxid: 0x300000006
Mode: follower # 集群模式，还有standalone单机模式
Node count: 13
[root@devops01 /opt/zookeeper]#
5.ruok ，判断节点是否运行，回复imok
[root@devops01 /opt/zookeeper]#echo ruok | nc 10.0.0.18 2181
imok[root@devops01 /opt/zookeeper]#
6.dump命令.
[root@devops01 /opt/zookeeper]#echo dump | nc 10.0.0.18 2181
SessionTracker dump:
Global Sessions(1):
0x1001aca8d1e0000 30000ms
ephemeral nodes dump:
Sessions with Ephemerals (0):
Connections dump:
Connections Sets (3)/(2):
0 expire at Sat Nov 12 01:44:13 CST 2022:
1 expire at Sat Nov 12 01:44:23 CST 2022:
ip: /10.0.0.18:43476 sessionId: 0x0 # 临时nc链接的会话
1 expire at Sat Nov 12 01:44:33 CST 2022:
ip: /127.0.0.1:41334 sessionId: 0x1001aca8d1e0000 # 有一个客户端
[root@devops01 /opt/zookeeper]#
6.1 创建临时节点，会被dump显示出来
[zk: localhost:2181(CONNECTED) 0] create -e /tmpChao
Created /tmpChao
[zk: localhost:2181(CONNECTED) 1] ls /
[chaoge, names, tmpChao, zookeeper]
[zk: localhost:2181(CONNECTED) 2]
7. isro 查看是否只读
[root@devops01 /opt/zookeeper]#
[root@devops01 /opt/zookeeper]#echo isro | nc 10.0.0.18 2181
rw[root@devops01 /opt/zookeeper]#
8.查看zk服务器端配置
[root@devops01 /opt/zookeeper]#echo conf | nc 10.0.0.18 2181
clientPort=2181
secureClientPort=-1
dataDir=/opt/zookeeper/zkData/version-2
dataDirSize=268436634
dataLogDir=/opt/zookeeper/zkData/version-2
dataLogSize=268436634
tickTime=2000
maxClientCnxns=60
minSessionTimeout=4000
maxSessionTimeout=40000
serverId=1
initLimit=10
syncLimit=5
electionAlg=3
electionPort=3888
quorumPort=2888
peerType=0
membership:
server.1=10.0.0.18:2888:3888:participant
server.2=10.0.0.19:2888:3888:participant
server.3=10.0.0.20:2888:3888:participant
version=0[root@devops01 /opt/zookeeper]#
# author by ,www.yuchaoit.cn
9. cons展示链接到服务器的客户端列表
[root@devops01 /opt/zookeeper]#echo cons | nc 10.0.0.18 2181
/127.0.0.1:41398[1](queued=0,recved=2,sent=2,sid=0x1001ad2288d0000,lop=PING,est=1668189236891,to=30000,lcxid=0x0,lzxid=0xffffffffffffffff,lresp=450673669,llat=0,minlat=0,avglat=0,maxlat=0)
/10.0.0.18:43540[0](queued=0,recved=1,sent=0)
[root@devops01 /opt/zookeeper]#
10. 显示默认zk的变量
[root@devops01 /opt/zookeeper]#echo envi | nc 10.0.0.18 2181
Environment:
zookeeper.version=3.5.6-c11b7e26bc554b8523dc929761dd28808913f091, built on 10/08/2019 20:18 GMT
host.name=devops01
java.version=1.8.0_181
java.vendor=Oracle Corporation
java.home=/usr/java/jdk1.8.0_181-amd64/jre
java.class.path=/opt/zookeeper/bin/../zookeeper-server/target/classes:/opt/zookeeper/bin/../build/classes:/opt/zookeeper/bin/../zookeeper-server/target/lib/*.jar:/opt/zookeeper/bin/../build/lib/*.jar:/opt/zookeeper/bin/../lib/zookeeper-jute-3.5.6.jar:/opt/zookeeper/bin/../lib/zookeeper-3.5.6.jar:/opt/zookeeper/bin/../lib/slf4j-log4j12-1.7.25.jar:/opt/zookeeper/bin/../lib/slf4j-api-1.7.25.jar:/opt/zookeeper/bin/../lib/netty-transport-native-unix-common-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-transport-native-epoll-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-transport-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-resolver-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-handler-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-common-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-codec-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/netty-buffer-4.1.42.Final.jar:/opt/zookeeper/bin/../lib/log4j-1.2.17.jar:/opt/zookeeper/bin/../lib/json-simple-1.1.1.jar:/opt/zookeeper/bin/../lib/jline-2.11.jar:/opt/zookeeper/bin/../lib/jetty-util-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/jetty-servlet-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/jetty-server-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/jetty-security-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/jetty-io-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/jetty-http-9.4.17.v20190418.jar:/opt/zookeeper/bin/../lib/javax.servlet-api-3.1.0.jar:/opt/zookeeper/bin/../lib/jackson-databind-2.9.10.jar:/opt/zookeeper/bin/../lib/jackson-core-2.9.10.jar:/opt/zookeeper/bin/../lib/jackson-annotations-2.9.10.jar:/opt/zookeeper/bin/../lib/commons-cli-1.2.jar:/opt/zookeeper/bin/../lib/audience-annotations-0.5.0.jar:/opt/zookeeper/bin/../zookeeper-*.jar:/opt/zookeeper/bin/../zookeeper-server/src/main/resources/lib/*.jar:/opt/zookeeper/bin/../conf:
java.library.path=/usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib
java.io.tmpdir=/tmp
java.compiler=<NA>
os.name=Linux
os.arch=amd64
os.version=3.10.0-862.el7.x86_64
user.name=root
user.home=/root
user.dir=/opt/apache-zookeeper-3.5.6-bin
os.memory.free=43MB
os.memory.max=889MB
os.memory.total=57MB
[root@devops01 /opt/zookeeper]#
11. mntr 监控zk状态
[root@devops01 ~]#tail -1 /opt/zookeeper/conf/zoo.cfg
4lw.commands.whitelist=stat, ruok, conf, isro,dump,cons,envi,mntr
[root@devops01 ~]#
[root@devops01 ~]#echo mntr | nc localhost 2181
zk_version 3.5.6-c11b7e26bc554b8523dc929761dd28808913f091, built on 10/08/2019 20:18 GMT
zk_avg_latency 0
zk_max_latency 0
zk_min_latency 0
zk_packets_received 1
zk_packets_sent 0
zk_num_alive_connections 1
zk_outstanding_requests 0
zk_server_state follower
zk_znode_count 13 # 有几个znode
zk_watch_count 0
zk_ephemerals_count 0 # 有几个临时节点
zk_approximate_data_size 323
zk_open_file_descriptor_count 59
zk_max_file_descriptor_count 4096
[root@devops01 ~]#
12.wchs 展示watch监控器信息
[root@devops01 ~]#!tail
tail -1 /opt/zookeeper/conf/zoo.cfg
4lw.commands.whitelist=stat, ruok, conf, isro,dump,cons,envi,mntr ,wchs
[root@devops01 ~]#
[root@devops01 ~]#echo wchs | nc localhost 2181
0 connections watching 0 paths
Total watches:0
[root@devops01 ~]#
默认没有监听器，设置一个zk客户端
[zk: localhost:2181(CONNECTED) 0] get -w /names
null
[zk: localhost:2181(CONNECTED) 1] get -w /
[zk: localhost:2181(CONNECTED) 2]
再查询监听器
[root@devops01 ~]#echo wchs | nc localhost 2181
1 connections watching 2 paths
Total watches:2
[root@devops01 ~]#
13.
# wchp按监听的path分类显示
# wchc按会话显示监听器分类
[root@devops01 ~]#tail -1 /opt/zookeeper/conf/zoo.cfg
4lw.commands.whitelist=stat, ruok, conf, isro,dump,cons,envi,mntr ,wchs,wchp,wchc
[root@devops01 ~]#
[root@devops01 ~]#echo wchp | nc localhost 2181
/names
0x10028b867e30002
/
0x10028b867e30002
[root@devops01 ~]#echo wchc | nc localhost 2181
0x10028b867e30002
/names
/
[root@devops01 ~]#