zookeeper总结

​​​​​​zookeeper，是一个分布式服务框架，是Apache Hadoop 的一个子项目，它主要是用来解决分布式应用中经常遇到的一些数据管理问题，如：统一命名服务、状态同步服务、集群管理、分布式应用配置项的管理等。

每个子目录项如 NameService 都被称作为 znode(目录节点)，和文件系统一样，我们能够自由的增加、删除znode，在一个znode下增加、删除子znode，唯一的不同在于znode是可以存储数据的。

有四种类型的znode：

• PERSISTENT-持久化目录节点

       客户端与zookeeper断开连接后，该节点依旧存在

• PERSISTENT_SEQUENTIAL-持久化顺序编号目录节点

       客户端与zookeeper断开连接后，该节点依旧存在，只是Zookeeper给该节点名称进行顺序编号

• EPHEMERAL-临时目录节点

       客户端与zookeeper断开连接后，该节点被删除

• EPHEMERAL_SEQUENTIAL-临时顺序编号目录节点

       客户端与zookeeper断开连接后，该节点被删除，只是Zookeeper给该节点名称进行顺序编号

下载地址

https://downloads.apache.org/zookeeper/zookeeper-3.5.8/
wget https://downloads.apache.org/zookeeper/zookeeper-3.5.8/apache-zookeeper-3.5.8-bin.tar.gz

cfg.zoo配置

# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial 
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between 
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just 
# example sakes.
dataDir=/home/hadoop/soft/zookeeper
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the 
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
server.1=192.168.153.131:28888:3888
server.2=192.168.153.134:28888:3888
server.3=192.168.153.135:28888:3888

配置参数说明

标识Server ID

[hadoop@master conf]$ mkdir /home/hadoop/soft/zookeeper
[hadoop@master conf]$ cd /home/hadoop/soft/zookeeper
[hadoop@master zookeeper]$ echo 1 >myid
[hadoop@master zookeeper]$ cat myid
1

复制zookeeper文件到其他服务器

scp -r /home/hadoop/soft/apache-zookeeper-3.5.8 slave1:/home/hadoop/soft
scp -r /home/hadoop/soft/apache-zookeeper-3.5.8 slave2:/home/hadoop/soft

修改其他服务器的Server ID

[hadoop@slave1 ~]$ mkdir /home/hadoop/soft/zookeeper
[hadoop@slave1 ~]$ echo 2 >myid
[hadoop@slave1 ~]$ cat myid
 
[hadoop@slave2 ~]$ mkdir /home/hadoop/soft/zookeeper
[hadoop@slave2 ~]$ echo 3 >myid

启动

[hadoop@master apache-zookeeper-3.5.8]$ ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[hadoop@master apache-zookeeper-3.5.8]$ pwd
/home/hadoop/soft/apache-zookeeper-3.5.8
[hadoop@master apache-zookeeper-3.5.8]$ ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Mode: follower
 
 
[hadoop@slave2 apache-zookeeper-3.5.8]$ ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[hadoop@slave2 apache-zookeeper-3.5.8]$ ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Mode: leader
 
[hadoop@slave1 apache-zookeeper-3.5.8]$ ./bin/zkServer.sh start
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Starting zookeeper ... STARTED
[hadoop@slave1 apache-zookeeper-3.5.8]$ ./bin/zkServer.sh status
ZooKeeper JMX enabled by default
Using config: /home/hadoop/soft/apache-zookeeper-3.5.8/bin/../conf/zoo.cfg
Client port found: 2181. Client address: localhost.
Mode: follower

查看进程

[hadoop@slave1 apache-zookeeper-3.5.8]$ jps
1700 QuorumPeerMain
1782 ZooKeeperMain
1885 Jps
 
[hadoop@slave2 apache-zookeeper-3.5.8]$ jps
1562 Jps
1374 QuorumPeerMain
 
[hadoop@master apache-zookeeper-3.5.8]$ jps
1586 QuorumPeerMain
1764 Jps

查看zookeeper目录

[hadoop@slave1 apache-zookeeper-3.5.8]$ ./bin/zkCli.sh
[zk: localhost:2181(CONNECTED) 0] ls /
[zookeeper]
[zk: localhost:2181(CONNECTED) 1] create /zmw
Created /zmw
[zk: localhost:2181(CONNECTED) 2] ls /
[zmw, zookeeper]
[zk: localhost:2181(CONNECTED) 3] create /test testData
Created /test
[zk: localhost:2181(CONNECTED) 4] ls /
[test, zmw, zookeeper]
[zk: localhost:2181(CONNECTED) 5] get /test
testData