curator实现master选举

最新推荐文章于 2022-03-13 23:29:04 发布

翻译最新推荐文章于 2022-03-13 23:29:04 发布 · 633 阅读

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#zookeeper leader选举

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本文介绍如何使用Apache Curator库在Zookeeper集群中实现Leader选举机制。通过示例代码展示了如何创建多个参与者竞争Leader角色，并在获得Leader身份后执行特定任务。

<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-framework</artifactId>
    <version>2.11.0</version>
</dependency>

<dependency>
    <groupId>org.apache.curator</groupId>
    <artifactId>curator-recipes</artifactId>
    <version>2.11.0</version>
</dependency>

public class CuratorLeaderTest {
    private static String ZK_URL = "192.168.1.45:2181,192.168.1.46:2181,192.168.1.41:2181";
    private static final String ROOT_MASTER="/master";//根节点
    public static void main(String[] args) throws InterruptedException, IOException {
        LeaderSelectorListener listener = new LeaderSelectorListener() {
            @Override
            public void takeLeadership(CuratorFramework client) throws Exception {
                System.out.println(Thread.currentThread().getName() + " 当选leader！");
                //调用takeLeadership方法进行业务逻辑处理，处理完成即释放领导权，可以写个死循环 不释放 leader
//                while (true) {
//                    System.out.println("状态："+client.getState());
//                    Thread.sleep(3000L);
//                }
                Thread.sleep(3000L);
                System.out.println(Thread.currentThread().getName() + " 放弃leader！");
            }

            @Override
            public void stateChanged(CuratorFramework client, ConnectionState state) {
            }
        };
        CountDownLatch countDownLatch = new CountDownLatch(1);
        for (int i = 0; i < 10; i++) {
            new Thread(() -> {
                try {
                    countDownLatch.await();
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                registerListener(listener);
            }).start();
            
        }
        TimeUnit.MILLISECONDS.sleep(50);
        countDownLatch.countDown();

        System.in.read();
    }
    private static void registerListener(LeaderSelectorListener listener) {
        CuratorFramework client = CuratorFrameworkFactory.newClient(ZK_URL,
                5000,5000, new ExponentialBackoffRetry(1000,5));
        client.start();

        try {
            new EnsurePath(ROOT_MASTER).ensure(client.getZookeeperClient());
        } catch (Exception e) {
            e.printStackTrace();
        }
        LeaderSelector selector = new LeaderSelector(client, ROOT_MASTER, listener);
        selector.autoRequeue();
        selector.start();
    }
}