YARN-6015. AsyncDispatcher thread name can be set to improved debugging. Contributed by Ajith S.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/event/AsyncDispatcher.java

@@ -74,6 +74,11 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
   protected final Map<Class<? extends Enum>, EventHandler> eventDispatchers;
   private boolean exitOnDispatchException;
 
+  /**
+   * The thread name for dispatcher.
+   */
+  private String dispatcherThreadName = "AsyncDispatcher event handler";
+
   public AsyncDispatcher() {
     this(new LinkedBlockingQueue<Event>());
   }
@@ -84,6 +89,15 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
     this.eventDispatchers = new HashMap<Class<? extends Enum>, EventHandler>();
   }
 
+  /**
+   * Set a name for this dispatcher thread.
+   * @param dispatcherName name of the dispatcher thread
+   */
+  public AsyncDispatcher(String dispatcherName) {
+    this();
+    dispatcherThreadName = dispatcherName;
+  }
+
   Runnable createThread() {
     return new Runnable() {
       @Override
@@ -130,7 +144,7 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
     //start all the components
     super.serviceStart();
     eventHandlingThread = new Thread(createThread());
-    eventHandlingThread.setName("AsyncDispatcher event handler");
+    eventHandlingThread.setName(dispatcherThreadName);
     eventHandlingThread.start();
   }
 

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/nodelabels/CommonNodeLabelsManager.java

@@ -211,7 +211,7 @@ public class CommonNodeLabelsManager extends AbstractService {
   // for UT purpose
   protected void initDispatcher(Configuration conf) {
     // create async handler
-    dispatcher = new AsyncDispatcher();
+    dispatcher = new AsyncDispatcher("NodeLabelManager dispatcher");
     AsyncDispatcher asyncDispatcher = (AsyncDispatcher) dispatcher;
     asyncDispatcher.init(conf);
     asyncDispatcher.setDrainEventsOnStop();

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/NodeManager.java

@@ -311,7 +311,7 @@ public class NodeManager extends CompositeService
     addService(del);
 
     // NodeManager level dispatcher
-    this.dispatcher = new AsyncDispatcher();
+    this.dispatcher = new AsyncDispatcher("NM Event dispatcher");
 
     dirsHandler = new LocalDirsHandlerService(metrics);
     nodeHealthChecker =

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/ContainerManagerImpl.java

@@ -218,7 +218,7 @@ public class ContainerManagerImpl extends CompositeService implements
     this.dirsHandler = dirsHandler;
 
     // ContainerManager level dispatcher.
-    dispatcher = new AsyncDispatcher();
+    dispatcher = new AsyncDispatcher("NM ContainerManager dispatcher");
     this.deletionService = deletionContext;
     this.metrics = metrics;
 

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

@@ -388,7 +388,7 @@ public class ResourceManager extends CompositeService implements Recoverable {
   }
 
   protected Dispatcher createDispatcher() {
-    return new AsyncDispatcher();
+    return new AsyncDispatcher("RM Event dispatcher");
   }
 
   protected ResourceScheduler createScheduler() {

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

@@ -355,7 +355,7 @@ public class RMApplicationHistoryWriter extends CompositeService {
     }
 
     protected AsyncDispatcher createDispatcher() {
-      return new AsyncDispatcher();
+      return new AsyncDispatcher("RM ApplicationHistory dispatcher");
     }
 
   }

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

@@ -634,7 +634,7 @@ public class SystemMetricsPublisher extends CompositeService {
     }
 
     protected AsyncDispatcher createDispatcher() {
-      return new AsyncDispatcher();
+      return new AsyncDispatcher("RM Timeline dispatcher");
     }
 
   }

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

@@ -678,7 +678,7 @@ public abstract class RMStateStore extends AbstractService {
   @Override
   protected void serviceInit(Configuration conf) throws Exception{
     // create async handler
-    dispatcher = new AsyncDispatcher();
+    dispatcher = new AsyncDispatcher("RM StateStore dispatcher");
     dispatcher.init(conf);
     rmStateStoreEventHandler = new ForwardingEventHandler();
     dispatcher.register(RMStateStoreEventType.class,