MAPREDUCE-2783. Fixing RM web-UI to show no tracking-URL when AM crashes. Contributed by Eric Payne.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1179975 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -1534,6 +1534,9 @@ Release 0.23.0 - Unreleased
     MAPREDUCE-2794. [MR-279] Incorrect metrics value for AvailableGB per 
     queue per user. (John George via mahadev)
 
+    MAPREDUCE-2783. Fixing RM web-UI to show no tracking-URL when AM
+    crashes. (Eric Payne via vinodkv)
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java

@@ -777,6 +777,15 @@ public class RMAppAttemptImpl implements RMAppAttempt {
             " due to: " +  containerStatus.getDiagnostics() + "." +
             "Failing this attempt.");
 
+        /*
+         * In the case when the AM dies, the trackingUrl is left pointing to the AM's
+         * URL, which shows up in the scheduler UI as a broken link. Setting it here
+         * to empty string will prevent any link from being displayed.
+         * NOTE: don't set trackingUrl to 'null'. That will cause null-pointer exceptions
+         * in the generated proto code.
+         */
+        appAttempt.trackingUrl = "";
+
         new FinalTransition(RMAppAttemptState.FAILED).transition(
             appAttempt, containerFinishedEvent);
         return RMAppAttemptState.FAILED;