YARN-4574. Fix random failure in TestAMRMClientOnRMRestart. (Takashi Ohnishi via rohithsharmaks)

(cherry picked from commit 34a3900773df6d9075dcf5476e8fe5208cd8f806)

hadoop-yarn-project/CHANGES.txt

@@ -88,6 +88,9 @@ Release 2.9.0 - UNRELEASED
     YARN-4497. RM might fail to restart when recovering apps whose attempts are missing.
     (Jun Gong via rohithsharmaks)
 
+    YARN-4574. Fix random failure in TestAMRMClientOnRMRestart.
+    (Takashi Ohnishi via rohithsharmaks)
+
 Release 2.8.0 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-client/src/test/java/org/apache/hadoop/yarn/client/api/impl/TestAMRMClientOnRMRestart.java

@@ -219,6 +219,7 @@ public class TestAMRMClientOnRMRestart {
     // request
     nm1.nodeHeartbeat(containerId.getApplicationAttemptId(),
         containerId.getContainerId(), ContainerState.RUNNING);
+    dispatcher.await();
     amClient.requestContainerResourceChange(
         container, Resource.newInstance(2048, 1));
     it.remove();