HDFS-15561. RBF: Remove NPE when local namenode is not configured (#2954). Contributed by Fengnan Li.

Reviewed-by: He Xiaoqiao <hexiaoqiao@apache.org>

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/Router.java

@@ -550,14 +550,20 @@ public class Router extends CompositeService implements
    *
    * @return Updater of the status for the local Namenode.
    */
-  protected NamenodeHeartbeatService createLocalNamenodeHeartbeatService() {
+  @VisibleForTesting
+  public NamenodeHeartbeatService createLocalNamenodeHeartbeatService() {
     // Detect NN running in this machine
     String nsId = DFSUtil.getNamenodeNameServiceId(conf);
+    if (nsId == null) {
+      LOG.error("Cannot find local nameservice id");
+      return null;
+    }
     String nnId = null;
     if (HAUtil.isHAEnabled(conf, nsId)) {
       nnId = HAUtil.getNameNodeId(conf, nsId);
       if (nnId == null) {
         LOG.error("Cannot find namenode id for local {}", nsId);
+        return null;
       }
     }
 
@@ -787,4 +793,13 @@ public class Router extends CompositeService implements
     return adminServer;
   }
 
+  /**
+   * Set router configuration.
+   * @param conf
+   */
+  @VisibleForTesting
+  public void setConf(Configuration conf) {
+    this.conf = conf;
+  }
+
 }

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterNamenodeHeartbeat.java

@@ -17,15 +17,21 @@
  */
 package org.apache.hadoop.hdfs.server.federation.router;
 
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_HA_NAMENODES_KEY_PREFIX;
+import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMESERVICES;
+import static org.apache.hadoop.hdfs.client.HdfsClientConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY;
 import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.NAMENODES;
 import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.NAMESERVICES;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
 
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
 
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.DFSUtil;
 import org.apache.hadoop.hdfs.server.federation.MockResolver;
 import org.apache.hadoop.hdfs.server.federation.MiniRouterDFSCluster;
 import org.apache.hadoop.hdfs.server.federation.MiniRouterDFSCluster.NamenodeContext;
@@ -105,6 +111,38 @@ public class TestRouterNamenodeHeartbeat {
     server.close();
   }
 
+  @Test
+  public void testLocalNamenodeHeartbeatService() throws IOException {
+    Router router = new Router();
+    Configuration conf = new Configuration();
+    assertEquals(null, DFSUtil.getNamenodeNameServiceId(conf));
+
+    // case 1: no local nn is configured
+    router.setConf(conf);
+    assertNull(router.createLocalNamenodeHeartbeatService());
+
+    // case 2: local nn is configured
+    conf.set(DFS_NAMESERVICES, "ns1");
+    assertEquals("ns1", DFSUtil.getNamenodeNameServiceId(conf));
+    conf.set(DFSUtil.addKeySuffixes(DFS_HA_NAMENODES_KEY_PREFIX, "ns1"),
+        "nn1,nn2");
+    conf.set(DFSUtil.addKeySuffixes(
+        DFS_NAMENODE_RPC_ADDRESS_KEY, "ns1", "nn1"),
+        "localhost:8020");
+    conf.set(DFSUtil.addKeySuffixes(
+        DFS_NAMENODE_RPC_ADDRESS_KEY, "ns1", "nn2"),
+        "ns1-nn2.example.com:8020");
+    router.setConf(conf);
+    NamenodeHeartbeatService heartbeatService =
+        router.createLocalNamenodeHeartbeatService();
+    assertNotNull(heartbeatService);
+    // we have to start the service to get the serviceAddress assigned
+    heartbeatService.init(conf);
+    assertEquals("ns1-nn1:localhost:8020",
+        heartbeatService.getNamenodeDesc());
+    heartbeatService.stop();
+  }
+
   @Test
   public void testHearbeat() throws InterruptedException, IOException {
 

hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterWebHdfsMethods.java

@@ -61,6 +61,7 @@ public class TestRouterWebHdfsMethods {
         .admin()
         .build();
     cluster.addRouterOverrides(conf);
+    cluster.setIndependentDNs();
     cluster.startCluster();
     cluster.startRouters();
     cluster.waitClusterUp();