HDFS-2724. NN web UI can throw NPE after startup, before standby state is entered. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1623@1229466 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/ha/HAServiceProtocol.java

@@ -36,9 +36,11 @@ public interface HAServiceProtocol extends VersionedProtocol {
   public static final long versionID = 1L;
 
   /**
-   * An HA service may be in active or standby state.
+   * An HA service may be in active or standby state. During
+   * startup, it is in an unknown INITIALIZING state.
    */
   public enum HAServiceState {
+    INITIALIZING("initializing"),
     ACTIVE("active"),
     STANDBY("standby");
 

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt

@@ -91,3 +91,5 @@ HDFS-2709. Appropriately handle error conditions in EditLogTailer (atm via todd)
 HDFS-2730. Refactor shared HA-related test code into HATestUtil class (todd)
 
 HDFS-2762. Fix TestCheckpoint timing out on HA branch. (Uma Maheswara Rao G via todd)
+
+HDFS-2724. NN web UI can throw NPE after startup, before standby state is entered. (todd)

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

@@ -926,6 +926,9 @@ public class NameNode {
   }
 
   synchronized HAServiceState getServiceState() {
+    if (state == null) {
+      return HAServiceState.INITIALIZING;
+    }
     return state.getServiceState();
   }
 

hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/dfshealth.jsp

@@ -31,7 +31,7 @@
   NameNode nn = NameNodeHttpServer.getNameNodeFromContext(application);
   FSNamesystem fsn = nn.getNamesystem();
   String namenodeRole = nn.getRole().toString();
-  String namenodeState = HAServiceState.ACTIVE.equals(nn.getServiceState()) ? "active" : "standby";
+  String namenodeState = nn.getServiceState().toString();
   String namenodeLabel = nn.getNameNodeAddress().getHostName() + ":" + nn.getNameNodeAddress().getPort();
 %>