YARN-1047. Expose # of pre-emptions as a queue counter (Contributed by Karthik Kambatla via Daniel Templeton)

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

@@ -71,6 +71,8 @@ public class QueueMetrics implements MetricsSource {
   @Metric("Aggregate # of allocated off-switch containers")
     MutableCounterLong aggregateOffSwitchContainersAllocated;
   @Metric("Aggregate # of released containers") MutableCounterLong aggregateContainersReleased;
+  @Metric("Aggregate # of preempted containers") MutableCounterLong
+      aggregateContainersPreempted;
   @Metric("Available memory in MB") MutableGaugeLong availableMB;
   @Metric("Available CPU in virtual cores") MutableGaugeInt availableVCores;
   @Metric("Pending memory allocation in MB") MutableGaugeLong pendingMB;
@@ -476,6 +478,13 @@ public void releaseResources(String user, Resource res) {
     }
   }
 
+  public void preemptContainer() {
+    aggregateContainersPreempted.incr();
+    if (parent != null) {
+      parent.preemptContainer();
+    }
+  }
+
   public void reserveResource(String user, Resource res) {
     reservedContainers.incr();
     reservedMB.incr(res.getMemorySize());
@@ -640,4 +649,8 @@ public long getAggregateOffSwitchContainersAllocated() {
   public long getAggegatedReleasedContainers() {
     return aggregateContainersReleased.value();
   }
+
+  public long getAggregatePreemptedContainers() {
+    return aggregateContainersPreempted.value();
+  }
 }

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

@@ -45,6 +45,7 @@
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerNode;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.PendingAsk;
 import org.apache.hadoop.yarn.server.scheduler.SchedulerRequestKey;
 import org.apache.hadoop.yarn.server.utils.BuilderUtils;
@@ -161,6 +162,10 @@ void containerCompleted(RMContainer rmContainer,
       }
 
       untrackContainerForPreemption(rmContainer);
+      if (containerStatus.getDiagnostics().
+          equals(SchedulerUtils.PREEMPTED_CONTAINER)) {
+        queue.getMetrics().preemptContainer();
+      }
 
       Resource containerResource = rmContainer.getContainer().getResource();
       RMAuditLogger.logSuccess(getUser(), AuditConstants.RELEASE_CONTAINER,

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

@@ -284,14 +284,20 @@ private void verifyPreemption(int numStarvedAppContainers)
       Thread.sleep(10);
     }
 
-    // Verify the right amount of containers are preempted from greedyApp
+    // Post preemption, verify the greedyApp has the correct # of containers.
-    assertEquals("Incorrect number of containers on the greedy app",
+    assertEquals("Incorrect # of containers on the greedy app",
         2 * numStarvedAppContainers, greedyApp.getLiveContainers().size());
 
+    // Verify the queue metrics are set appropriately. The greedyApp started
+    // with 8 1GB, 1vcore containers.
+    assertEquals("Incorrect # of preempted containers in QueueMetrics",
+        8 - 2 * numStarvedAppContainers,
+        greedyApp.getQueue().getMetrics().getAggregatePreemptedContainers());
+
     sendEnoughNodeUpdatesToAssignFully();
 
     // Verify the preempted containers are assigned to starvingApp
-    assertEquals("Starved app is not assigned the right number of containers",
+    assertEquals("Starved app is not assigned the right # of containers",
         numStarvedAppContainers, starvingApp.getLiveContainers().size());
   }