YARN-3435. AM container to be allocated Appattempt AM container shown as

null. Contributed by Bibin A Chundatt

(cherry picked from commit 96d72118f5c81aa4e0dca0dc0241fbf1a3fff4d2)

hadoop-yarn-project/CHANGES.txt

@@ -94,6 +94,9 @@ Release 2.8.0 - UNRELEASED
     YARN-3415. Non-AM containers can be counted towards amResourceUsage of a
     Fair Scheduler queue (Zhihai Xu via Sandy Ryza)
 
+    YARN-3435. AM container to be allocated Appattempt AM container shown as null.
+    (Bibin A Chundatt via xgong)
+
 Release 2.7.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/RMAppAttemptBlock.java

@@ -209,7 +209,7 @@ public class RMAppAttemptBlock extends AppAttemptBlock{
         "AM Container:",
         appAttempt.getAmContainerId() == null || containers == null
             || !hasAMContainer(appAttemptReport.getAMContainerId(), containers)
-            ? null : root_url("container", appAttempt.getAmContainerId()),
+            ? "N/A" : root_url("container", appAttempt.getAmContainerId()),
         String.valueOf(appAttempt.getAmContainerId()))
       ._("Node:", node)
       ._(