快速学习-Zookeeper分布式安装部署

cwl_java

发布于 2020-03-25 17:26:50

4270

发布于 2020-03-25 17:26:50

文章被收录于专栏：cwl_Javacwl_Java

第4章 Zookeeper实战（开发重点）

4.1 分布式安装部署

1．集群规划在hadoop102、hadoop103和hadoop104三个节点上部署Zookeeper。 2．解压安装（1）解压Zookeeper安装包到/opt/module/目录下

[atguigu@hadoop102 software]$ tar -zxvf zookeeper-3.4.10.tar.gz -C /opt/module/

（2）同步/opt/module/zookeeper-3.4.10目录内容到hadoop103、hadoop104

[atguigu@hadoop102 module]$ xsync zookeeper-3.4.10/

3．配置服务器编号（1）在/opt/module/zookeeper-3.4.10/这个目录下创建zkData

[atguigu@hadoop102 zookeeper-3.4.10]$ mkdir -p zkData

（2）在/opt/module/zookeeper-3.4.10/zkData目录下创建一个myid的文件

[atguigu@hadoop102 zkData]$ touch myid

添加myid文件，注意一定要在linux里面创建，在notepad++里面很可能乱码（3）编辑myid文件

[atguigu@hadoop102 zkData]$ vi myid

在文件中添加与server对应的编号：

2 （4）拷贝配置好的zookeeper到其他机器上

[atguigu@hadoop102 zkData]$ xsync myid

并分别在hadoop102、hadoop103上修改myid文件中内容为3、4 4．配置zoo.cfg文件（1）重命名/opt/module/zookeeper-3.4.10/conf这个目录下的zoo_sample.cfg为zoo.cfg

[atguigu@hadoop102 conf]$ mv zoo_sample.cfg zoo.cfg

（2）打开zoo.cfg文件

[atguigu@hadoop102 conf]$ vim zoo.cfg

修改数据存储路径配置

dataDir=/opt/module/zookeeper-3.4.10/zkData

增加如下配置

#######################cluster##########################
server.2=hadoop102:2888:3888
server.3=hadoop103:2888:3888
server.4=hadoop104:2888:3888

（3）同步zoo.cfg配置文件

[atguigu@hadoop102 conf]$ xsync zoo.cfg

（4）配置参数解读

server.A=B:C:D。

A是一个数字，表示这个是第几号服务器；集群模式下配置一个文件myid，这个文件在dataDir目录下，这个文件里面有一个数据就是A的值，Zookeeper启动时读取此文件，拿到里面的数据与zoo.cfg里面的配置信息比较从而判断到底是哪个server。 B是这个服务器的ip地址； C是这个服务器与集群中的Leader服务器交换信息的端口； D是万一集群中的Leader服务器挂了，需要一个端口来重新进行选举，选出一个新的Leader，而这个端口就是用来执行选举时服务器相互通信的端口。 4．集群操作（1）分别启动Zookeeper

[atguigu@hadoop102 zookeeper-3.4.10]$ bin/zkServer.sh start
[atguigu@hadoop103 zookeeper-3.4.10]$ bin/zkServer.sh start
[atguigu@hadoop104 zookeeper-3.4.10]$ bin/zkServer.sh start

（2）查看状态

[atguigu@hadoop102 zookeeper-3.4.10]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: follower
[atguigu@hadoop103 zookeeper-3.4.10]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: leader
[atguigu@hadoop104 zookeeper-3.4.5]# bin/zkServer.sh status
JMX enabled by default
Using config: /opt/module/zookeeper-3.4.10/bin/../conf/zoo.cfg
Mode: follower

4.2 客户端命令行操作

1．启动客户端

[atguigu@hadoop103 zookeeper-3.4.10]$ bin/zkCli.sh

2．显示所有操作命令

[zk: localhost:2181(CONNECTED) 1] help

3．查看当前znode中所包含的内容

[zk: localhost:2181(CONNECTED) 0] ls /
[zookeeper]

4．查看当前节点详细数据

[zk: localhost:2181(CONNECTED) 1] ls2 /
[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

5．分别创建2个普通节点

[zk: localhost:2181(CONNECTED) 3] create /sanguo "jinlian"
Created /sanguo
[zk: localhost:2181(CONNECTED) 4] create /sanguo/shuguo "liubei"
Created /sanguo/shuguo

6．获得节点的值

[zk: localhost:2181(CONNECTED) 5] get /sanguo
jinlian
cZxid = 0x100000003
ctime = Wed Aug 29 00:03:23 CST 2018
mZxid = 0x100000003
mtime = Wed Aug 29 00:03:23 CST 2018
pZxid = 0x100000004
cversion = 1
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 7
numChildren = 1
[zk: localhost:2181(CONNECTED) 6]
[zk: localhost:2181(CONNECTED) 6] get /sanguo/shuguo
liubei
cZxid = 0x100000004
ctime = Wed Aug 29 00:04:35 CST 2018
mZxid = 0x100000004
mtime = Wed Aug 29 00:04:35 CST 2018
pZxid = 0x100000004
cversion = 0
dataVersion = 0
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 6
numChildren = 0

7．创建短暂节点

[zk: localhost:2181(CONNECTED) 7] create -e /sanguo/wuguo "zhouyu"
Created /sanguo/wuguo

（1）在当前客户端是能查看到的

[zk: localhost:2181(CONNECTED) 3] ls /sanguo 
[wuguo, shuguo]

（2）退出当前客户端然后再重启客户端

[zk: localhost:2181(CONNECTED) 12] quit
[atguigu@hadoop104 zookeeper-3.4.10]$ bin/zkCli.sh

（3）再次查看根目录下短暂节点已经删除

[zk: localhost:2181(CONNECTED) 0] ls /sanguo
[shuguo]

8．创建带序号的节点（1）先创建一个普通的根节点/sanguo/weiguo

[zk: localhost:2181(CONNECTED) 1] create /sanguo/weiguo "caocao"
Created /sanguo/weiguo

（2）创建带序号的节点

[zk: localhost:2181(CONNECTED) 2] create -s /sanguo/weiguo/xiaoqiao "jinlian"
Created /sanguo/weiguo/xiaoqiao0000000000
[zk: localhost:2181(CONNECTED) 3] create -s /sanguo/weiguo/daqiao "jinlian"
Created /sanguo/weiguo/daqiao0000000001
[zk: localhost:2181(CONNECTED) 4] create -s /sanguo/weiguo/diaocan "jinlian"
Created /sanguo/weiguo/diaocan0000000002

如果原来没有序号节点，序号从0开始依次递增。如果原节点下已有2个节点，则再排序时从2开始，以此类推。 9．修改节点数据值

[zk: localhost:2181(CONNECTED) 6] set /sanguo/weiguo "simayi"

10．节点的值变化监听（1）在hadoop104主机上注册监听/sanguo节点数据变化

[zk: localhost:2181(CONNECTED) 26] [zk: localhost:2181(CONNECTED) 8] get /sanguo watch

（2）在hadoop103主机上修改/sanguo节点的数据

[zk: localhost:2181(CONNECTED) 1] set /sanguo "xisi"

（3）观察hadoop104主机收到数据变化的监听

WATCHER::
WatchedEvent state:SyncConnected type:NodeDataChanged path:/sanguo

11．节点的子节点变化监听（路径变化）（1）在hadoop104主机上注册监听/sanguo节点的子节点变化

[zk: localhost:2181(CONNECTED) 1] ls /sanguo watch
[aa0000000001, server101]

（2）在hadoop103主机/sanguo节点上创建子节点

[zk: localhost:2181(CONNECTED) 2] create /sanguo/jin "simayi"
Created /sanguo/jin

（3）观察hadoop104主机收到子节点变化的监听

WATCHER::
WatchedEvent state:SyncConnected type:NodeChildrenChanged path:/sanguo

12．删除节点

[zk: localhost:2181(CONNECTED) 4] delete /sanguo/jin

13．递归删除节点

[zk: localhost:2181(CONNECTED) 15] rmr /sanguo/shuguo

14．查看节点状态

[zk: localhost:2181(CONNECTED) 17] stat /sanguo
cZxid = 0x100000003
ctime = Wed Aug 29 00:03:23 CST 2018
mZxid = 0x100000011
mtime = Wed Aug 29 00:21:23 CST 2018
pZxid = 0x100000014
cversion = 9
dataVersion = 1
aclVersion = 0
ephemeralOwner = 0x0
dataLength = 4
numChildren = 1

4.3 API应用

4.3.1 Eclipse环境搭建

1．创建一个Maven工程 2．添加pom文件

<dependencies>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>RELEASE</version>
		</dependency>
		<dependency>
			<groupId>org.apache.logging.log4j</groupId>
			<artifactId>log4j-core</artifactId>
			<version>2.8.2</version>
		</dependency>
		<!-- https://mvnrepository.com/artifact/org.apache.zookeeper/zookeeper -->
		<dependency>
			<groupId>org.apache.zookeeper</groupId>
			<artifactId>zookeeper</artifactId>
			<version>3.4.10</version>
		</dependency>
</dependencies>

3．拷贝log4j.properties文件到项目根目录需要在项目的src/main/resources目录下，新建一个文件，命名为“log4j.properties”，在文件中填入。

log4j.rootLogger=INFO, stdout  
log4j.appender.stdout=org.apache.log4j.ConsoleAppender  
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout  
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n  
log4j.appender.logfile=org.apache.log4j.FileAppender  
log4j.appender.logfile.File=target/spring.log  
log4j.appender.logfile.layout=org.apache.log4j.PatternLayout  
log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n

4.3.2 创建ZooKeeper客户端

private static String connectString =
 "hadoop102:2181,hadoop103:2181,hadoop104:2181";
	private static int sessionTimeout = 2000;
	private ZooKeeper zkClient = null;

	@Before
	public void init() throws Exception {

	zkClient = new ZooKeeper(connectString, sessionTimeout, new Watcher() {

			@Override
			public void process(WatchedEvent event) {

				// 收到事件通知后的回调函数（用户的业务逻辑）
				System.out.println(event.getType() + "--" + event.getPath());

				// 再次启动监听
				try {
					zkClient.getChildren("/", true);
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

4.3.3 创建子节点

// 创建子节点
@Test
public void create() throws Exception {

		// 参数1：要创建的节点的路径； 参数2：节点数据 ； 参数3：节点权限 ；参数4：节点的类型
		String nodeCreated = zkClient.create("/atguigu", "jinlian".getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.PERSISTENT);
}

4.3.4 获取子节点并监听节点变化

// 获取子节点
@Test
public void getChildren() throws Exception {

		List<String> children = zkClient.getChildren("/", true);

		for (String child : children) {
			System.out.println(child);
		}

		// 延时阻塞
		Thread.sleep(Long.MAX_VALUE);
}

4.3.5 判断Znode是否存在

// 判断znode是否存在
@Test
public void exist() throws Exception {

	Stat stat = zkClient.exists("/eclipse", false);

	System.out.println(stat == null ? "not exist" : "exist");
}

4.4 监听服务器节点动态上下线案例

1．需求某分布式系统中，主节点可以有多台，可以动态上下线，任意一台客户端都能实时感知到主节点服务器的上下线。 2．需求分析，如图5-12所示

3．具体实现（0）先在集群上创建/servers节点

[zk: localhost:2181(CONNECTED) 10] create /servers "servers"
Created /servers

（1）服务器端向Zookeeper注册代码

public class DistributeServer {

	private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
	private static int sessionTimeout = 2000;
	private ZooKeeper zk = null;
	private String parentNode = "/servers";
	
	// 创建到zk的客户端连接
	public void getConnect() throws IOException{
		
		zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {

			@Override
			public void process(WatchedEvent event) {

			}
		});
	}
	
	// 注册服务器
	public void registServer(String hostname) throws Exception{

		String create = zk.create(parentNode + "/server", hostname.getBytes(), Ids.OPEN_ACL_UNSAFE, CreateMode.EPHEMERAL_SEQUENTIAL);
		
		System.out.println(hostname +" is online "+ create);
	}
	
	// 业务功能
	public void business(String hostname) throws Exception{
		System.out.println(hostname+" is working ...");
		
		Thread.sleep(Long.MAX_VALUE);
	}
	
	public static void main(String[] args) throws Exception {
		
// 1获取zk连接
		DistributeServer server = new DistributeServer();
		server.getConnect();
		
		// 2 利用zk连接注册服务器信息
		server.registServer(args[0]);
		
		// 3 启动业务功能
		server.business(args[0]);
	}
}

（2）客户端代码

public class DistributeClient {

	private static String connectString = "hadoop102:2181,hadoop103:2181,hadoop104:2181";
	private static int sessionTimeout = 2000;
	private ZooKeeper zk = null;
	private String parentNode = "/servers";

	// 创建到zk的客户端连接
	public void getConnect() throws IOException {
		zk = new ZooKeeper(connectString, sessionTimeout, new Watcher() {

			@Override
			public void process(WatchedEvent event) {

				// 再次启动监听
				try {
					getServerList();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});
	}

	// 获取服务器列表信息
	public void getServerList() throws Exception {
		
		// 1获取服务器子节点信息，并且对父节点进行监听
		List<String> children = zk.getChildren(parentNode, true);

        // 2存储服务器信息列表
		ArrayList<String> servers = new ArrayList<>();
		
        // 3遍历所有节点，获取节点中的主机名称信息
		for (String child : children) {
			byte[] data = zk.getData(parentNode + "/" + child, false, null);

			servers.add(new String(data));
		}

        // 4打印服务器列表信息
		System.out.println(servers);
	}

	// 业务功能
	public void business() throws Exception{

		System.out.println("client is working ...");
Thread.sleep(Long.MAX_VALUE);
	}

	public static void main(String[] args) throws Exception {

		// 1获取zk连接
		DistributeClient client = new DistributeClient();
		client.getConnect();

		// 2获取servers的子节点信息，从中获取服务器信息列表
		client.getServerList();

		// 3业务进程启动
		client.business();
	}
}

本文参与腾讯云自媒体分享计划，分享自作者个人站点/博客。

原始发表：2020-03-24 ，如有侵权请联系 cloudcommunity@tencent.com 删除

zookeeper

本文分享自作者个人站点/博客前往查看

如有侵权，请联系 cloudcommunity@tencent.com 删除。

本文参与腾讯云自媒体分享计划，欢迎热爱写作的你一起参与！

zookeeper

登录后参与评论

0 条评论

热度