1.简介
ZooKeeper是一个为分布式应用所设计的分布的、开源的协调服务，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，简化分布式应用协调及其管理的难度，提供高性能的分布式服务。ZooKeeper本身可以以Standalone模式安装运行，不过它的长处在于通过分布式ZooKeeper集群（一个Leader，多个Follower），基于一定的策略来保证ZooKeeper集群的稳定性和可用性，从而实现分布式应用的可靠性。
ZooKeeper是作为分布式协调服务，是不需要依赖于Hadoop的环境，也可以为其他的分布式环境提供服务。
2. 单节点安装
下载,解压,配置
cd /data0/java/deploy/
curl -O http://apache.mirrors.tds.net/zookeeper/stable/zookeeper-3.4.6.tar.gz
# 解压
tar xzvf zookeeper-3.4.6.tar.gz
mv zookeeper-3.4.6 zookeeper346
cd zookeeper346/conf
cp zoo_sample.cfg zoo.cfg
vim zoo.cfg
修改内容如下, 需手动创建定义的数据目录
dataDir=/data0/java/deploy/zookeeper/nodes/zk0
启动
# zookeeper 可执行文件目录
cd ../bin
./zkServer.sh start
至此单节点配置,启动完成.
启动 ：./zkServer.sh start
停止 ：./zkServer.sh stop
查看状态 ：./zkServer.sh status
3 .集群安装
集群中节点树结构
└── nodes
├── zk0
│ └── version-2
│ └── log.1
├── zk1
│ ├── data
│ │ ├── myid
│ │ └── version-2
│ │ ├── acceptedEpoch
│ │ ├── currentEpoch
│ │ └── snapshot.0
│ └── logs
│ └── version-2
│ └── log.100000001
├── zk2
│ ├── data
│ │ ├── myid
│ │ └── version-2
│ │ ├── acceptedEpoch
│ │ └── currentEpoch
│ └── logs
│ └── version-2
│ └── log.100000001
└── zk3
├── data
│ ├── myid
│ └── version-2
│ ├── acceptedEpoch
│ ├── currentEpoch
│ └── snapshot.100000000
└── logs
└── version-2
└── log.100000001
配置节点一
配置文件(/data0/java/deploy/zookeeper/conf/zk1.cfg)
dataDir=/data0/java/deploy/zookeeper/nodes/zk1/data
dataLogDir=/data0/java/deploy/zookeeper/nodes/zk1/logs
clientPort=2181
# 集群实例
server.1=127.0.0.1:2888:3888
server.2=127.0.0.1:2889:3889
server.3=127.0.0.1:2890:3890
根据dataDir,dataLogDir创建相应的目录并在data目录执行如下命令
echo 1 > myid
配置节点二
不解释, 直接上配置文件(/data0/java/deploy/zookeeper/conf/zk2.cfg)
dataDir=/data0/java/deploy/zookeeper/nodes/zk2/data
dataLogDir=/data0/java/deploy/zookeeper/nodes/zk2/logs
clientPort=2182
# 集群实例
server.1=127.0.0.1:2888:3888
server.2=127.0.0.1:2889:3889
server.3=127.0.0.1:2890:3890
根据dataDir,dataLogDir创建相应的目录并在data目录执行如下命令
echo 2 > myid
配置节点三
不解释, 直接上配置文件(/data0/java/deploy/zookeeper/conf/zk3.cfg)
dataDir=/data0/java/deploy/zookeeper/nodes/zk3/data
dataLogDir=/data0/java/deploy/zookeeper/nodes/zk3/logs
clientPort=2183
# 集群实例
server.1=127.0.0.1:2888:3888
server.2=127.0.0.1:2889:3889
server.3=127.0.0.1:2890:3890
根据dataDir,dataLogDir创建相应的目录并在data目录执行如下命令
echo 3 > myid
启动Zookeeper集群
# zookeeper可执行文件目录
cd bin
./zkServer.sh start zk1.cfg
./zkServer.sh start zk2.cfg
./zkServer.sh start zk3.cfg
查看Zookeeper集群中各个节点的状态
./zkServer.sh status zk1.cfg
JMX enabled by default
Using config: /data0/java/deploy/zookeeper/bin/../conf/zk1.cfg
Mode: follower
./zkServer.sh status zk2.cfg
JMX enabled by default
Using config: /data0/java/deploy/zookeeper/bin/../conf/zk2.cfg
Mode: leader
./zkServer.sh status zk3.cfg
JMX enabled by default
Using config: /data0/java/deploy/zookeeper/bin/../conf/zk3.cfg
Mode: follower
注: 可以考虑多种启动或停止zookeeper的情况进行状态查看, 可发现zookeeper的高可用(HA);
4.命令行操作
4.1 使用命令行client连接zookeeper并操作API
连接到任意节点
./zkCli.sh -server 127.0.0.1:2182
4.2 help 查看指令
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
4.3其他常用命令
- 查看/目录节点
ls / - 创建znode节点
create /config db.properties - 查看/下节点, ls /
[config, zookeeper] - 查看节点内容, get /config
db.properties
cZxid = 0x300000011
ctime = Fri Nov 14 23:05:05 CST 2014
mZxid = 0x300000011
mtime = Fri Nov 14 23:05:05 CST 2014
pZxid = 0x300000011
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 13
numChildren = 0
- 修改节点内容, set /config db2.properties
- 再次查看 get /config
db2.properties
cZxid = 0x300000011
ctime = Fri Nov 14 23:05:05 CST 2014
mZxid = 0x300000012
mtime = Fri Nov 14 23:08:10 CST 2014
pZxid = 0x300000011
cversion = 0
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 14
numChildren = 0
- 删除节点, delete /config
- 查看, ls /
- 退出, quit
5.Java操作
源码
package com.yangyang.zookeeper;
import java.io.IOException;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.WatchedEvent;
import org.apache.zookeeper.Watcher;
import org.apache.zookeeper.ZooDefs.Ids;
import org.apache.zookeeper.ZooKeeper;
/**
* Java 操作zookeeper API
*
*/
public class Main
{
public static void main( String[] args ) throws IOException, InterruptedException, KeeperException
{
// 创建连接
ZooKeeper zk = new ZooKeeper("127.0.0.1:2182", 30000, new Watcher(){
// 监听的事件发生变化时, 调用该函数
public void process(WatchedEvent event) {
System.out.println("Event emit -> " + event.getType());
}
});
// 查看根目录, ls /
System.out.println("[line: 29]command: ls / -> " + zk.getChildren("/", true));
// 创建数据节点config
if(zk.exists("/config", true) == null) {
zk.create("/config", "db.properties".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
System.out.println("创建数据节点config成功.");
// 查看数据节点数据
System.out.println("[line: 38]command get /config: " + new String(zk.getData("/config", true, null)));
// 查看根目录, ls /
System.out.println("[line: 41]command: ls / -> " + zk.getChildren("/", true));
}
// 修改数据节点
if(zk.exists("/config", true) != null) {
zk.setData("/config", "db2.properteis".getBytes(), -1);
// 查看数据节点数据
System.out.println("[line: 48]command get /config: " + new String(zk.getData("/config", true, null)));
// 查看根目录, ls /
System.out.println("[line: 50]command: ls / -> " + zk.getChildren("/", true));
}
// 删除数据节点
if(zk.exists("/config", true) != null) {
zk.delete("/config", -1);
// 查看根目录, ls /
System.out.println("[line: 57]command: ls / -> " + zk.getChildren("/", true));
}
// 关闭连接
zk.close();
}
}
结果
Event emit -> None
[line: 29]command: ls / -> [zookeeper]
Event emit -> NodeCreated
Event emit -> NodeChildrenChanged
创建数据节点config成功.
[line: 38]command get /config: db.properties
[line: 41]command: ls / -> [config, zookeeper]
Event emit -> NodeDataChanged
[line: 48]command get /config: db2.properteis
[line: 50]command: ls / -> [config, zookeeper]
Event emit -> NodeDeleted
Event emit -> NodeChildrenChanged
[line: 57]command: ls / -> [zookeeper]
参考资料
ZooKeeper伪分布式集群安装及使用
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