YARN-9615. Add dispatcher metrics to RM. Contributed by Jonathan Hung and Qi Zhu.

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

@@ -26,6 +26,9 @@ import java.util.Map;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 
+import org.apache.hadoop.yarn.metrics.EventTypeMetrics;
+import org.apache.hadoop.yarn.util.Clock;
+import org.apache.hadoop.yarn.util.MonotonicClock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.Marker;
@@ -85,6 +88,11 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
   protected final Map<Class<? extends Enum>, EventHandler> eventDispatchers;
   private boolean exitOnDispatchException = true;
 
+  private Map<Class<? extends Enum>,
+      EventTypeMetrics> eventTypeMetricsMap;
+
+  private Clock clock = new MonotonicClock();
+
   /**
    * The thread name for dispatcher.
    */
@@ -98,6 +106,8 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
     super("Dispatcher");
     this.eventQueue = eventQueue;
     this.eventDispatchers = new HashMap<Class<? extends Enum>, EventHandler>();
+    this.eventTypeMetricsMap = new HashMap<Class<? extends Enum>,
+        EventTypeMetrics>();
   }
 
   /**
@@ -135,7 +145,16 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
             return;
           }
           if (event != null) {
-            dispatch(event);
+            if (eventTypeMetricsMap.
+                get(event.getType().getDeclaringClass()) != null) {
+              long startTime = clock.getTime();
+              dispatch(event);
+              eventTypeMetricsMap.get(event.getType().getDeclaringClass())
+                  .increment(event.getType(),
+                      clock.getTime() - startTime);
+            } else {
+              dispatch(event);
+            }
             if (printTrigger) {
               //Log the latest dispatch event type
               // may cause the too many events queued
@@ -369,4 +388,9 @@ public class AsyncDispatcher extends AbstractService implements Dispatcher {
   protected boolean isStopped() {
     return stopped;
   }
+
+  public void addMetrics(EventTypeMetrics metrics,
+      Class<? extends Enum> eventClass) {
+    eventTypeMetricsMap.put(eventClass, metrics);
+  }
 }

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

@@ -19,6 +19,9 @@
 package org.apache.hadoop.yarn.event;
 
 import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
+import org.apache.hadoop.yarn.metrics.EventTypeMetrics;
+import org.apache.hadoop.yarn.util.Clock;
+import org.apache.hadoop.yarn.util.MonotonicClock;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.Marker;
@@ -47,12 +50,15 @@ public class EventDispatcher<T extends Event> extends
   private final Thread eventProcessor;
   private volatile boolean stopped = false;
   private boolean shouldExitOnError = true;
+  private EventTypeMetrics metrics;
 
   private static final Logger LOG =
       LoggerFactory.getLogger(EventDispatcher.class);
   private static final Marker FATAL =
       MarkerFactory.getMarker("FATAL");
 
+  private Clock clock = new MonotonicClock();
+
   private final class EventProcessor implements Runnable {
     @Override
     public void run() {
@@ -68,7 +74,14 @@ public class EventDispatcher<T extends Event> extends
         }
 
         try {
-          handler.handle(event);
+          if (metrics != null) {
+            long startTime = clock.getTime();
+            handler.handle(event);
+            metrics.increment(event.getType(),
+                clock.getTime() - startTime);
+          } else {
+            handler.handle(event);
+          }
         } catch (Throwable t) {
           // An error occurred, but we are shutting down anyway.
           // If it was an InterruptedException, the very act of
@@ -136,4 +149,9 @@ public class EventDispatcher<T extends Event> extends
   public void disableExitOnError() {
     shouldExitOnError = false;
   }
+
+  public void setMetrics(EventTypeMetrics metrics) {
+    this.metrics = metrics;
+  }
+
 }

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/metrics/DisableEventTypeMetrics.java

@@ -0,0 +1,42 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.yarn.metrics;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.metrics2.MetricsCollector;
+import org.apache.hadoop.metrics2.annotation.Metrics;
+
+@InterfaceAudience.Private
+@Metrics(context="yarn")
+public class DisableEventTypeMetrics implements EventTypeMetrics {
+  @Override
+  public void increment(Enum type, long processingTimeUs) {
+    //nop
+    return;
+  }
+  @Override
+  public void getMetrics(MetricsCollector collector, boolean all) {
+    //nop
+    return;
+  }
+
+  @Override
+  public long get(Enum type) {
+    return 0;
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/metrics/EventTypeMetrics.java

@@ -0,0 +1,32 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.yarn.metrics;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.metrics2.MetricsSource;
+import org.apache.hadoop.metrics2.annotation.Metrics;
+
+@InterfaceAudience.Private
+@Metrics(context="yarn")
+public interface EventTypeMetrics<T extends Enum<T>>
+    extends MetricsSource {
+
+  void increment(T type, long processingTimeUs);
+
+  long get(T type);
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/metrics/GenericEventTypeMetrics.java

@@ -0,0 +1,160 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.yarn.metrics;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.metrics2.MetricsCollector;
+import org.apache.hadoop.metrics2.MetricsInfo;
+import org.apache.hadoop.metrics2.MetricsSystem;
+import org.apache.hadoop.metrics2.annotation.Metrics;
+import org.apache.hadoop.metrics2.lib.MetricsRegistry;
+import org.apache.hadoop.metrics2.lib.MutableGaugeLong;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.EnumMap;
+
+@InterfaceAudience.Private
+@Metrics(context="yarn")
+public class GenericEventTypeMetrics<T extends Enum<T>>
+    implements EventTypeMetrics<T> {
+
+  static final Logger LOG =
+      LoggerFactory.getLogger(GenericEventTypeMetrics.class);
+
+  private final EnumMap<T, MutableGaugeLong> eventCountMetrics;
+  private final EnumMap<T, MutableGaugeLong> processingTimeMetrics;
+  private final MetricsRegistry registry;
+  private final MetricsSystem ms;
+  private final MetricsInfo info;
+  private final Class<T> enumClass;
+
+  private boolean isInitialized = false;
+
+  public GenericEventTypeMetrics(MetricsInfo info, MetricsSystem ms,
+                                 final T[] enums, Class<T> enumClass) {
+    this.enumClass = enumClass;
+    this.eventCountMetrics = new EnumMap<>(this.enumClass);
+    this.processingTimeMetrics = new EnumMap<>(this.enumClass);
+    this.ms = ms;
+    this.info = info;
+    this.registry = new MetricsRegistry(this.info);
+
+    //Initialize enum
+    for (final T type : enums) {
+      String eventCountMetricsName =
+          type.toString() + "_" + "event_count";
+      String processingTimeMetricsName =
+          type.toString() + "_" + "processing_time";
+      eventCountMetrics.put(type, this.registry.
+          newGauge(eventCountMetricsName, eventCountMetricsName, 0L));
+      processingTimeMetrics.put(type, this.registry.
+          newGauge(processingTimeMetricsName, processingTimeMetricsName, 0L));
+    }
+  }
+
+  public synchronized GenericEventTypeMetrics registerMetrics() {
+    if (!isInitialized) {
+      // Register with the MetricsSystems
+      if (this.ms != null) {
+        LOG.info("Registering GenericEventTypeMetrics");
+        ms.register(info.name(),
+            info.description(), this);
+        isInitialized = true;
+      }
+    }
+    return this;
+  }
+
+  @Override
+  public void increment(T type, long processingTimeUs) {
+    if (eventCountMetrics.get(type) != null) {
+      eventCountMetrics.get(type).incr();
+      processingTimeMetrics.get(type).incr(processingTimeUs);
+    }
+  }
+
+  @Override
+  public long get(T type) {
+    return eventCountMetrics.get(type).value();
+  }
+
+  public long getTotalProcessingTime(T type) {
+    return processingTimeMetrics.get(type).value();
+  }
+
+  public EnumMap<T, MutableGaugeLong> getEventCountMetrics() {
+    return eventCountMetrics;
+  }
+
+  public EnumMap<T, MutableGaugeLong> getProcessingTimeMetrics() {
+    return processingTimeMetrics;
+  }
+
+  public MetricsRegistry getRegistry() {
+    return registry;
+  }
+
+  public MetricsInfo getInfo() {
+    return info;
+  }
+
+  @Override
+  public void getMetrics(MetricsCollector collector, boolean all) {
+    registry.snapshot(collector.addRecord(registry.info()), all);
+  }
+
+  public Class<T> getEnumClass() {
+    return enumClass;
+  }
+
+  /** Builder class for GenericEventTypeMetrics. */
+  public static class EventTypeMetricsBuilder<T extends Enum<T>>{
+    public EventTypeMetricsBuilder() {
+    }
+
+    public EventTypeMetricsBuilder setEnumClass(Class<T> enumClassValue) {
+      this.enumClass = enumClassValue;
+      return this;
+    }
+
+    public EventTypeMetricsBuilder setEnums(T[] enumsValue) {
+      this.enums = enumsValue.clone();
+      return this;
+    }
+
+    public EventTypeMetricsBuilder setInfo(MetricsInfo infoValue) {
+      this.info = infoValue;
+      return this;
+    }
+
+    public EventTypeMetricsBuilder setMs(MetricsSystem msValue) {
+      this.ms = msValue;
+      return this;
+    }
+
+    public GenericEventTypeMetrics build() {
+      return new GenericEventTypeMetrics(info, ms, enums, enumClass);
+    }
+
+    private MetricsSystem ms;
+    private MetricsInfo info;
+    private Class<T> enumClass;
+    private T[] enums;
+  }
+}

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/event/TestAsyncDispatcher.java

@@ -20,9 +20,20 @@ package org.apache.hadoop.yarn.event;
 
 import java.lang.reflect.Field;
 import java.lang.reflect.Modifier;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.Map;
+import java.util.Set;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.LinkedBlockingQueue;
 
+
+import org.apache.hadoop.metrics2.AbstractMetric;
+import org.apache.hadoop.metrics2.MetricsRecord;
+import org.apache.hadoop.metrics2.impl.MetricsCollectorImpl;
+import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.apache.hadoop.yarn.metrics.GenericEventTypeMetrics;
 import org.slf4j.Logger;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.yarn.conf.YarnConfiguration;
@@ -30,6 +41,7 @@ import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
 import org.junit.Assert;
 import org.junit.Test;
 
+import static org.apache.hadoop.metrics2.lib.Interns.info;
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.*;
 
@@ -118,7 +130,7 @@ public class TestAsyncDispatcher {
   }
 
   private enum TestEnum {
-    TestEventType
+    TestEventType, TestEventType2
   }
 
   @SuppressWarnings({ "rawtypes", "unchecked" })
@@ -230,5 +242,171 @@ public class TestAsyncDispatcher {
     }
   }
 
-}
+  @Test
+  public void testMetricsForDispatcher() throws Exception {
+    YarnConfiguration conf = new YarnConfiguration();
+    AsyncDispatcher dispatcher = null;
+
+    try {
+      dispatcher = new AsyncDispatcher("RM Event dispatcher");
+
+      GenericEventTypeMetrics genericEventTypeMetrics =
+          new GenericEventTypeMetrics.EventTypeMetricsBuilder()
+              .setMs(DefaultMetricsSystem.instance())
+              .setInfo(info("GenericEventTypeMetrics for "
+                      + TestEnum.class.getName(),
+                  "Metrics for " + dispatcher.getName()))
+              .setEnumClass(TestEnum.class)
+              .setEnums(TestEnum.class.getEnumConstants())
+              .build().registerMetrics();
+
+      // We can the metrics enabled for TestEnum
+      dispatcher.addMetrics(genericEventTypeMetrics,
+          genericEventTypeMetrics.getEnumClass());
+      dispatcher.init(conf);
+
+      // Register handler
+      dispatcher.register(TestEnum.class, new TestHandler());
+      dispatcher.start();
+
+      for (int i = 0; i < 3; ++i) {
+        Event event = mock(Event.class);
+        when(event.getType()).thenReturn(TestEnum.TestEventType);
+        dispatcher.getEventHandler().handle(event);
+      }
+
+      for (int i = 0; i < 2; ++i) {
+        Event event = mock(Event.class);
+        when(event.getType()).thenReturn(TestEnum.TestEventType2);
+        dispatcher.getEventHandler().handle(event);
+      }
+
+      // Check event type count.
+      GenericTestUtils.waitFor(() -> genericEventTypeMetrics.
+          get(TestEnum.TestEventType) == 3, 1000, 10000);
+
+      GenericTestUtils.waitFor(() -> genericEventTypeMetrics.
+          get(TestEnum.TestEventType2) == 2, 1000, 10000);
+
+      // Check time spend.
+      Assert.assertTrue(genericEventTypeMetrics.
+          getTotalProcessingTime(TestEnum.TestEventType)
+          >= 1500*3);
+      Assert.assertTrue(genericEventTypeMetrics.
+          getTotalProcessingTime(TestEnum.TestEventType)
+          < 1500*4);
+
+      Assert.assertTrue(genericEventTypeMetrics.
+          getTotalProcessingTime(TestEnum.TestEventType2)
+          >= 1500*2);
+      Assert.assertTrue(genericEventTypeMetrics.
+          getTotalProcessingTime(TestEnum.TestEventType2)
+          < 1500*3);
+
+      // Make sure metrics consistent.
+      Assert.assertEquals(Long.toString(genericEventTypeMetrics.
+              get(TestEnum.TestEventType)),
+          genericEventTypeMetrics.
+              getRegistry().get("TestEventType_event_count").toString());
+      Assert.assertEquals(Long.toString(genericEventTypeMetrics.
+              get(TestEnum.TestEventType2)),
+          genericEventTypeMetrics.
+              getRegistry().get("TestEventType2_event_count").toString());
+      Assert.assertEquals(Long.toString(genericEventTypeMetrics.
+              getTotalProcessingTime(TestEnum.TestEventType)),
+          genericEventTypeMetrics.
+              getRegistry().get("TestEventType_processing_time").toString());
+      Assert.assertEquals(Long.toString(genericEventTypeMetrics.
+              getTotalProcessingTime(TestEnum.TestEventType2)),
+          genericEventTypeMetrics.
+              getRegistry().get("TestEventType2_processing_time").toString());
+
+    } finally {
+      dispatcher.close();
+    }
+
+  }
+
+  @Test
+  public void testDispatcherMetricsHistogram() throws Exception {
+    YarnConfiguration conf = new YarnConfiguration();
+    AsyncDispatcher dispatcher = null;
+
+    try {
+      dispatcher = new AsyncDispatcher("RM Event dispatcher");
+
+      GenericEventTypeMetrics genericEventTypeMetrics =
+          new GenericEventTypeMetrics.EventTypeMetricsBuilder()
+              .setMs(DefaultMetricsSystem.instance())
+              .setInfo(info("GenericEventTypeMetrics for "
+                      + TestEnum.class.getName(),
+                  "Metrics for " + dispatcher.getName()))
+              .setEnumClass(TestEnum.class)
+              .setEnums(TestEnum.class.getEnumConstants())
+              .build().registerMetrics();
+
+      // We can the metrics enabled for TestEnum
+      dispatcher.addMetrics(genericEventTypeMetrics,
+          genericEventTypeMetrics.getEnumClass());
+      dispatcher.init(conf);
+
+      // Register handler
+      dispatcher.register(TestEnum.class, new TestHandler());
+      dispatcher.start();
+
+      for (int i = 0; i < 3; ++i) {
+        Event event = mock(Event.class);
+        when(event.getType()).thenReturn(TestEnum.TestEventType);
+        dispatcher.getEventHandler().handle(event);
+      }
+
+      for (int i = 0; i < 2; ++i) {
+        Event event = mock(Event.class);
+        when(event.getType()).thenReturn(TestEnum.TestEventType2);
+        dispatcher.getEventHandler().handle(event);
+      }
+
+      // Check event type count.
+      GenericTestUtils.waitFor(() -> genericEventTypeMetrics.
+          get(TestEnum.TestEventType) == 3, 1000, 10000);
+
+      GenericTestUtils.waitFor(() -> genericEventTypeMetrics.
+          get(TestEnum.TestEventType2) == 2, 1000, 10000);
+
+      // submit actual values
+      Map<String, Long> expectedValues = new HashMap<>();
+      expectedValues.put("TestEventType_event_count",
+          genericEventTypeMetrics.get(TestEnum.TestEventType));
+      expectedValues.put("TestEventType_processing_time",
+          genericEventTypeMetrics.
+              getTotalProcessingTime(TestEnum.TestEventType));
+      expectedValues.put("TestEventType2_event_count",
+          genericEventTypeMetrics.get(TestEnum.TestEventType2));
+      expectedValues.put("TestEventType2_processing_time",
+          genericEventTypeMetrics.
+              getTotalProcessingTime(TestEnum.TestEventType2));
+      Set<String> testResults = new HashSet<>();
 
+      MetricsCollectorImpl collector = new MetricsCollectorImpl();
+      genericEventTypeMetrics.getMetrics(collector, true);
+
+      for (MetricsRecord record : collector.getRecords()) {
+        for (AbstractMetric metric : record.metrics()) {
+          String metricName = metric.name();
+          if (expectedValues.containsKey(metricName)) {
+            Long expectedValue = expectedValues.get(metricName);
+            Assert.assertEquals(
+                "Metric " + metricName + " doesn't have expected value",
+                expectedValue, metric.value());
+            testResults.add(metricName);
+          }
+        }
+      }
+      Assert.assertEquals(expectedValues.keySet(), testResults);
+
+    } finally {
+      dispatcher.close();
+    }
+
+  }
+}

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

@@ -0,0 +1,42 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.yarn.server.resourcemanager;
+
+import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
+import org.apache.hadoop.yarn.metrics.GenericEventTypeMetrics;
+
+import static org.apache.hadoop.metrics2.lib.Interns.info;
+
+public final class GenericEventTypeMetricsManager {
+
+  private GenericEventTypeMetricsManager() {
+    // nothing to do
+  }
+
+  // Construct a GenericEventTypeMetrics for dispatcher
+  public static <T extends Enum<T>> GenericEventTypeMetrics
+      create(String dispatcherName, Class<T> eventTypeClass) {
+    return new GenericEventTypeMetrics.EventTypeMetricsBuilder<T>()
+        .setMs(DefaultMetricsSystem.instance())
+        .setInfo(info("GenericEventTypeMetrics for " + eventTypeClass.getName(),
+            "Metrics for " + dispatcherName))
+        .setEnumClass(eventTypeClass)
+        .setEnums(eventTypeClass.getEnumConstants())
+        .build().registerMetrics();
+  }
+}

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

@@ -21,6 +21,7 @@ package org.apache.hadoop.yarn.server.resourcemanager;
 import org.apache.hadoop.thirdparty.com.google.common.annotations.VisibleForTesting;
 import com.sun.jersey.spi.container.servlet.ServletContainer;
 
+import org.apache.hadoop.yarn.metrics.GenericEventTypeMetrics;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.slf4j.Marker;
@@ -62,6 +63,7 @@ import org.apache.hadoop.yarn.event.AsyncDispatcher;
 import org.apache.hadoop.yarn.event.Dispatcher;
 import org.apache.hadoop.yarn.event.EventDispatcher;
 import org.apache.hadoop.yarn.event.EventHandler;
+
 import org.apache.hadoop.yarn.exceptions.YarnException;
 import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
 import org.apache.hadoop.yarn.nodelabels.NodeAttributesManager;
@@ -449,11 +451,23 @@ public class ResourceManager extends CompositeService
   }
 
   protected EventHandler<SchedulerEvent> createSchedulerEventDispatcher() {
-    return new EventDispatcher(this.scheduler, "SchedulerEventDispatcher");
+    EventDispatcher dispatcher = new
+        EventDispatcher(this.scheduler, "SchedulerEventDispatcher");
+    dispatcher.
+        setMetrics(GenericEventTypeMetricsManager.
+            create(dispatcher.getName(), SchedulerEventType.class));
+    return dispatcher;
   }
 
   protected Dispatcher createDispatcher() {
-    return new AsyncDispatcher("RM Event dispatcher");
+    AsyncDispatcher dispatcher = new AsyncDispatcher("RM Event dispatcher");
+    GenericEventTypeMetrics genericEventTypeMetrics =
+        GenericEventTypeMetricsManager.
+        create(dispatcher.getName(), NodesListManagerEventType.class);
+    // We can add more
+    dispatcher.addMetrics(genericEventTypeMetrics,
+        genericEventTypeMetrics.getEnumClass());
+    return dispatcher;
   }
 
   protected ResourceScheduler createScheduler() {

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

@@ -29,6 +29,7 @@ import java.util.concurrent.TimeoutException;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
 import org.apache.hadoop.http.lib.StaticUserWebFilter;
+import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.net.NetworkTopology;
 import org.apache.hadoop.security.AuthenticationFilterInitializer;
 import org.apache.hadoop.security.UserGroupInformation;
@@ -73,6 +74,7 @@ public class TestResourceManager {
   public void setUp() throws Exception {
     YarnConfiguration conf = new YarnConfiguration();
     UserGroupInformation.setConfiguration(conf);
+    DefaultMetricsSystem.setMiniClusterMode(true);
     resourceManager = new ResourceManager();
     resourceManager.init(conf);
     resourceManager.getRMContext().getContainerTokenSecretManager().rollMasterKey();

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

@@ -18,6 +18,7 @@
 
 package org.apache.hadoop.yarn.server.resourcemanager.scheduler;
 
+import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.net.NetworkTopology;
 import org.apache.hadoop.util.Time;
 import org.apache.hadoop.yarn.api.records.ContainerId;
@@ -52,6 +53,7 @@ public class TestSchedulerHealth {
   private ResourceManager resourceManager;
 
   public void setup() {
+    DefaultMetricsSystem.setMiniClusterMode(true);
     resourceManager = new ResourceManager() {
       @Override
       protected RMNodeLabelsManager createNodeLabelManager() {

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestCapacityScheduler.java

@@ -212,6 +212,7 @@ public class TestCapacityScheduler extends CapacitySchedulerTestBase {
   @Before
   public void setUp() throws Exception {
     ResourceUtils.resetResourceTypes(new Configuration());
+    DefaultMetricsSystem.setMiniClusterMode(true);
     resourceManager = new ResourceManager() {
       @Override
       protected RMNodeLabelsManager createNodeLabelManager() {