YARN-9763. Print application tags in application summary. Contributed by Manoj Kumar

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

@@ -21,6 +21,7 @@ import java.util.Collections;
 import java.util.LinkedList;
 import java.util.List;
 import java.util.Map;
+import java.util.TreeSet;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 
@@ -207,7 +208,10 @@ public class RMAppManager implements EventHandler<RMAppManagerEvent>,
               .getResourceSecondsString(metrics.getResourceSecondsMap()))
           .add("preemptedResourceSeconds", StringHelper
               .getResourceSecondsString(
-                  metrics.getPreemptedResourceSecondsMap()));
+                  metrics.getPreemptedResourceSecondsMap()))
+          .add("applicationTags", StringHelper.CSV_JOINER.join(
+              app.getApplicationTags() != null ? new TreeSet<>(
+                  app.getApplicationTags()) : Collections.<String>emptySet()));
       return summary;
     }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/TestAppManager.java

@@ -1071,6 +1071,7 @@ public class TestAppManager extends AppManagerTestBase{
     when(app.getApplicationType()).thenReturn("MAPREDUCE");
     when(app.getSubmitTime()).thenReturn(1000L);
     when(app.getLaunchTime()).thenReturn(2000L);
+    when(app.getApplicationTags()).thenReturn(Sets.newHashSet("tag2", "tag1"));
     Map<String, Long> resourceSecondsMap = new HashMap<>();
     resourceSecondsMap.put(ResourceInformation.MEMORY_MB.getName(), 16384L);
     resourceSecondsMap.put(ResourceInformation.VCORES.getName(), 64L);
@@ -1098,7 +1099,8 @@ public class TestAppManager extends AppManagerTestBase{
     assertTrue(msg.contains("preemptedNonAMContainers=10"));
     assertTrue(msg.contains("preemptedResources=<memory:1234\\, vCores:56>"));
     assertTrue(msg.contains("applicationType=MAPREDUCE"));
- }
+    assertTrue(msg.contains("applicationTags=tag1\\,tag2"));
+  }
 
   @Test
   public void testRMAppSubmitWithQueueChanged() throws Exception {