MAPREDUCE-3687. If AM dies before it returns new tracking URL, proxy redirects to http://N/A/ and doesn't return error code (Ravi Prakash via bobby)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1295147 13f79535-47bb-0310-9956-ffa450edef68

hadoop-mapreduce-project/CHANGES.txt

@@ -211,6 +211,10 @@ Release 0.23.2 - UNRELEASED
     so that race conditions don't fail tasks by inadvertantly changing the
     timestamps. (Siddarth Seth via vinodkv)
 
+    MAPREDUCE-3687.  If AM dies before it returns new tracking URL, proxy
+    redirects to http://N/A/ and doesn't return error code (Ravi Prakash via
+    bobby)
+
 Release 0.23.1 - 2012-02-17
 
   INCOMPATIBLE CHANGES

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-web-proxy/src/main/java/org/apache/hadoop/yarn/server/webproxy/WebAppProxyServlet.java

@@ -237,7 +237,11 @@ public class WebAppProxyServlet extends HttpServlet {
       }
       URI trackingUri = ProxyUriUtils.getUriFromAMUrl(
           applicationReport.getOriginalTrackingUrl());
-      
+      if(applicationReport.getOriginalTrackingUrl().equals("N/A")) {
+        notFound(resp, "The MRAppMaster died before writing anything.");
+        return;
+      }
+
       String runningUser = applicationReport.getUser();
       if(checkUser && !runningUser.equals(remoteUser)) {
         LOG.info("Asking "+remoteUser+" if they want to connect to the " +