有的時候，我們想知道Zookeeper叢集中哪些伺服器屬於Leader，哪些屬於Follower，哪些屬於Observer。

通過命令，可以很容易的獲取到Zookeeper伺服器的狀態：

[[email protected] bin]$ ./zkServer.sh status
JMX enabled by default
Using config: /home/hadoop/apache/zookeeper-3.4.5/bin/../conf/zoo.cfg
Mode: follower

public class ServerStatus {
	@Test
	public void serverStatus() throws IOException {
		String host = "10.0.1.84";
		int port = 2181;
		String cmd = "stat";

		Socket sock = new Socket(host, port);
		BufferedReader reader = null;
		try {
			OutputStream outstream = sock.getOutputStream();
			// 通過Zookeeper的四字命令獲取伺服器的狀態
			outstream.write(cmd.getBytes());
			outstream.flush();
			sock.shutdownOutput();

			reader = new BufferedReader(new InputStreamReader(sock.getInputStream()));
			String line;
			while ((line = reader.readLine()) != null) {
				if (line.indexOf("Mode: ") != -1) {
					System.out.println(line.replaceAll("Mode: ", "").trim());
				}
			}
		} finally {
			sock.close();
			if (reader != null) {
				reader.close();
			}
		}
	}
}
 

follower