YARN-2274. FairScheduler: Add debug information about cluster capacity, availability and reservations. (kasha)

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2@1610542 13f79535-47bb-0310-9956-ffa450edef68

hadoop-yarn-project/CHANGES.txt

@@ -22,6 +22,9 @@ Release 2.6.0 - UNRELEASED
     YARN-2242. Improve exception information on AM launch crashes. (Li Lu 
     via junping_du)
 
+    YARN-2274. FairScheduler: Add debug information about cluster capacity, 
+    availability and reservations. (kasha)
+
   OPTIMIZATIONS
 
   BUG FIXES

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

@@ -136,6 +136,8 @@ public class FairScheduler extends
 
   // How often fair shares are re-calculated (ms)
   protected long UPDATE_INTERVAL = 500;
+  private final int UPDATE_DEBUG_FREQUENCY = 5;
+  private int updatesToSkipForDebug = UPDATE_DEBUG_FREQUENCY;
 
   private Thread updateThread;
   private Thread schedulingThread;
@@ -275,6 +277,18 @@ public class FairScheduler extends
     // Recursively compute fair shares for all queues
     // and update metrics
     rootQueue.recomputeShares();
+
+    if (LOG.isDebugEnabled()) {
+      if (--updatesToSkipForDebug < 0) {
+        updatesToSkipForDebug = UPDATE_DEBUG_FREQUENCY;
+        LOG.debug("Cluster Capacity: " + clusterResource +
+            "  Allocations: " + rootMetrics.getAllocatedResources() +
+            "  Availability: " + Resource.newInstance(
+            rootMetrics.getAvailableMB(),
+            rootMetrics.getAvailableVirtualCores()) +
+            "  Demand: " + rootQueue.getDemand());
+      }
+    }
   }
 
   /**
@@ -879,14 +893,14 @@ public class FairScheduler extends
         // Update application requests
         application.updateResourceRequests(ask);
 
-        LOG.debug("allocate: post-update");
         application.showRequests();
       }
 
       if (LOG.isDebugEnabled()) {
-        LOG.debug("allocate:" +
+        LOG.debug("allocate: post-update" +
             " applicationAttemptId=" + appAttemptId +
-            " #ask=" + ask.size());
+            " #ask=" + ask.size() +
+            " reservation= " + application.getCurrentReservation());
 
         LOG.debug("Preempting " + application.getPreemptionContainers().size()
             + " container(s)");