HDFS-16547. [SBN read] Namenode in safe mode should not be transfer to observer state

Author: tomscut

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -1653,7 +1653,7 @@ && isInStartupSafeMode()) {
     }
   }
 
-  private SafeModeException newSafemodeException(String errorMsg) {
+  public SafeModeException newSafemodeException(String errorMsg) {
     return new SafeModeException(errorMsg + ". Name node is in safe " +
         "mode.\n" + getSafeModeTip() + " NamenodeHostName:" + nameNodeHostName);
   }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java

@@ -1899,6 +1899,10 @@ synchronized void transitionToStandby() throws IOException {
   synchronized void transitionToObserver() throws IOException {
     String operationName = "transitionToObserver";
     namesystem.checkSuperuserPrivilege(operationName);
+    if (namesystem.isInSafeMode()) {
+      throw namesystem.newSafemodeException("Cannot transition to " +
+          OBSERVER_STATE);
+    }
     if (!haEnabled) {
       throw new ServiceFailedException("HA for namenode is not enabled");
     }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSHAAdmin.java

@@ -262,8 +262,13 @@ private int transitionToObserver(final CommandLine cmd)
     if (!checkManualStateManagementOK(target)) {
       return -1;
     }
-    HAServiceProtocol proto = target.getProxy(getConf(), 0);
-    HAServiceProtocolHelper.transitionToObserver(proto, createReqInfo());
+    try {
+      HAServiceProtocol proto = target.getProxy(getConf(), 0);
+      HAServiceProtocolHelper.transitionToObserver(proto, createReqInfo());
+    } catch (IOException e) {
+      errOut.println("TransitionToObserver failed! " + e.getMessage());
+      return -1;
+    }
     return 0;
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/tools/TestDFSZKFailoverController.java

@@ -19,6 +19,7 @@
 
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_SERVICE_RPC_BIND_HOST_KEY;
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 
 import java.io.ByteArrayInputStream;
@@ -40,9 +41,11 @@
 import org.apache.hadoop.hdfs.DFSConfigKeys;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.MiniDFSNNTopology;
+import org.apache.hadoop.hdfs.protocol.HdfsConstants;
 import org.apache.hadoop.hdfs.server.namenode.EditLogFileOutputStream;
 import org.apache.hadoop.hdfs.server.namenode.MockNameNodeResourceChecker;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.hdfs.server.namenode.SafeModeException;
 import org.apache.hadoop.hdfs.server.namenode.ha.HATestUtil;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
 import org.apache.hadoop.net.ServerSocketUtil;
@@ -301,6 +304,40 @@ public void testManualFailoverWithDFSHAAdmin() throws Exception {
     waitForHAState(1, HAServiceState.STANDBY);
   }
 
+  /**
+   * Tests that a Namenode in safe mode should not be transfer to observer state.
+   */
+  @Test
+  public void testManualFailoverWithDFSHAAdminInSafemode() throws Exception {
+    startCluster();
+    NamenodeProtocols nn1 = cluster.getNameNode(1).getRpcServer();
+
+    // Enter safe mode.
+    nn1.setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_ENTER, false);
+    // Test NameNodeRpcServer.
+    LambdaTestUtils.intercept(SafeModeException.class,
+        "Cannot transition to observer. Name node is in safe mode",
+        () -> nn1.transitionToObserver(
+            new StateChangeRequestInfo(RequestSource.REQUEST_BY_USER_FORCED)));
+
+    // Test DFSHAAdmin.
+    DFSHAAdmin tool = new DFSHAAdmin();
+    tool.setConf(conf);
+    System.setIn(new ByteArrayInputStream("yes\n".getBytes()));
+    int result = tool.run(
+        new String[]{"-transitionToObserver", "-forcemanual", "nn2"});
+    assertEquals("State transition returned: " + result, -1, result);
+
+    // Leave safe mode.
+    nn1.setSafeMode(HdfsConstants.SafeModeAction.SAFEMODE_LEAVE, false);
+    // Just need to test DFSHAAdmin.
+    System.setIn(new ByteArrayInputStream("yes\n".getBytes()));
+    int result1 = tool.run(
+        new String[]{"-transitionToObserver", "-forcemanual", "nn2"});
+    assertEquals("State transition returned: " + result1, 0, result1);
+    assertFalse(cluster.getNameNode(1).isInSafeMode());
+  }
+
   @Test(timeout=30000)
   public void testElectionOnObserver() throws Exception{
     startCluster();