YARN-3495. Confusing log generated by FairScheduler. Contributed by Brahma Reddy Battula.

hadoop-yarn-project/CHANGES.txt

@@ -233,6 +233,9 @@ Release 2.8.0 - UNRELEASED
     YARN-3136. Fixed a synchronization problem of
     AbstractYarnScheduler#getTransferredContainers. (Sunil G via jianhe)
 
+    YARN-3495. Confusing log generated by FairScheduler.
+    (Brahma Reddy Battula via ozawa)
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/FairScheduler.java

@@ -796,7 +796,8 @@ private synchronized void removeApplicationAttempt(
   protected synchronized void completedContainer(RMContainer rmContainer,
       ContainerStatus containerStatus, RMContainerEventType event) {
     if (rmContainer == null) {
-      LOG.info("Null container completed...");
+      LOG.info("Container " + containerStatus.getContainerId()
+          + " completed with event " + event);
       return;
     }
 
@@ -809,7 +810,7 @@ protected synchronized void completedContainer(RMContainer rmContainer,
         container.getId().getApplicationAttemptId().getApplicationId();
     if (application == null) {
       LOG.info("Container " + container + " of" +
-          " unknown application attempt " + appId +
+          " finished application " + appId +
           " completed with event " + event);
       return;
     }