[MINOR] Fix BindException when running tests of shared machines. (#2070)

When unit tests are run on shared machines (e.g. jenkins cluster), the unit tests sometimes fail due to BindException in starting HDFS Cluster. This is because the port chosen may have been bound by another process using the same machine. The fix is to retry the port selection a few times.

hudi-common/src/test/java/org/apache/hudi/common/testutils/minicluster/HdfsTestService.java

@@ -31,6 +31,7 @@
 
 import java.io.File;
 import java.io.IOException;
+import java.net.BindException;
 import java.nio.file.Files;
 import java.util.Objects;
 
@@ -72,20 +73,32 @@ public MiniDFSCluster start(boolean format) throws IOException {
       FileIOUtils.deleteDirectory(file);
     }
 
-    int namenodeRpcPort = NetworkTestUtils.nextFreePort();
-    int datanodePort = NetworkTestUtils.nextFreePort();
-    int datanodeIpcPort = NetworkTestUtils.nextFreePort();
-    int datanodeHttpPort = NetworkTestUtils.nextFreePort();
-
-    // Configure and start the HDFS cluster
-    // boolean format = shouldFormatDFSCluster(localDFSLocation, clean);
-    String bindIP = "127.0.0.1";
-    configureDFSCluster(hadoopConf, localDFSLocation, bindIP, namenodeRpcPort,
-        datanodePort, datanodeIpcPort, datanodeHttpPort);
-    miniDfsCluster = new MiniDFSCluster.Builder(hadoopConf).numDataNodes(1).format(format).checkDataNodeAddrConfig(true)
-        .checkDataNodeHostConfig(true).build();
-    LOG.info("HDFS Minicluster service started.");
-    return miniDfsCluster;
+    int loop = 0;
+    while (true) {
+      try {
+        int namenodeRpcPort = NetworkTestUtils.nextFreePort();
+        int datanodePort = NetworkTestUtils.nextFreePort();
+        int datanodeIpcPort = NetworkTestUtils.nextFreePort();
+        int datanodeHttpPort = NetworkTestUtils.nextFreePort();
+
+        // Configure and start the HDFS cluster
+        // boolean format = shouldFormatDFSCluster(localDFSLocation, clean);
+        String bindIP = "127.0.0.1";
+        configureDFSCluster(hadoopConf, localDFSLocation, bindIP, namenodeRpcPort,
+            datanodePort, datanodeIpcPort, datanodeHttpPort);
+        miniDfsCluster = new MiniDFSCluster.Builder(hadoopConf).numDataNodes(1).format(format).checkDataNodeAddrConfig(true)
+            .checkDataNodeHostConfig(true).build();
+        LOG.info("HDFS Minicluster service started.");
+        return miniDfsCluster;
+      } catch (BindException ex) {
+        ++loop;
+        if (loop < 5) {
+          stop();
+        } else {
+          throw ex;
+        }
+      }
+    }
   }
 
   public void stop() {