由於工作需要，需要拿到當前叢集的Active Namenode的Ip地址，所以寫以下小程式碼，防止忘記，記錄一下：

import java.io.IOException;
import java.net.InetSocketAddress;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.hdfs.HAUtil;

public class ActiveNNAdd {

public void getNameNodeAdress() throws Exception {
Configuration conf = new Configuration();

FileSystem system = null;
try {
    system = FileSystem.get(conf);
    InetSocketAddress active = HAUtil.getAddressOfActive(system);
    System.out.println(active.getHostString()); 
    // System.out.println("hdfs port:" + active.getPort());
    // InetAddress address = active.getAddress();
    // System.out.println("hdfs://" + address.getHostAddress() + ":"+ active.getPort()); 
} catch (IOException e) {
    e.printStackTrace();
} finally {
    try {
        if (system != null) {
            system.close();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}


public static void main(String[] args) {

ActiveNNAdd nn = new ActiveNNAdd() ;

try {
    nn.getNameNodeAdress();
    } catch (Exception e) {
    e.printStackTrace();
    }
    }
}
 

  以上程式碼是使用Hadoop原始碼提供的HAUtil工具類來做的，有興趣的小夥伴還可以嘗試連線Zookeeper獲取！