diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index 412999f4d0f..9f0e8e1f971 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -542,6 +542,9 @@ Release 2.8.0 - UNRELEASED
     YARN-4405. Support node label store in non-appendable file system. (Wangda
     Tan via jianhe)
 
+    YARN-3946. Update exact reason as to why a submitted app is in ACCEPTED state to 
+    app's diagnostic message. (Naganarasimha G R via wangda)
+
   OPTIMIZATIONS
 
     YARN-3339. TestDockerContainerExecutor should pull a single image and not
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java
index 7a2b717cc73..c4c8d2eb33d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/RMAppImpl.java
@@ -645,7 +645,8 @@ public class RMAppImpl implements RMApp, Recoverable {
           progress = currentAttempt.getProgress();
           logAggregationStatus = this.getLogAggregationStatusForAppReport();
         }
-        diags = this.diagnostics.toString();
+        //if the diagnostics is not already set get it from attempt
+        diags = getDiagnostics().toString();
 
         if (currentAttempt != null && 
             currentAttempt.getAppAttemptState() == RMAppAttemptState.LAUNCHED) {
@@ -750,8 +751,13 @@ public class RMAppImpl implements RMApp, Recoverable {
   @Override
   public StringBuilder getDiagnostics() {
     this.readLock.lock();
-
     try {
+      if (diagnostics.length() == 0 && getCurrentAppAttempt() != null) {
+        String appAttemptDiagnostics = getCurrentAppAttempt().getDiagnostics();
+        if (appAttemptDiagnostics != null) {
+          return new StringBuilder(appAttemptDiagnostics);
+        }
+      }
       return this.diagnostics;
     } finally {
       this.readLock.unlock();
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttempt.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttempt.java
index 4dd834580b0..91aee402829 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttempt.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttempt.java
@@ -246,4 +246,10 @@ public interface RMAppAttempt extends EventHandler<RMAppAttemptEvent> {
    * @return the finish time of the application attempt.
    */
   long getFinishTime();
+
+  /**
+   * To capture Launch diagnostics of the app.
+   * @param amLaunchDiagnostics
+   */
+  void updateAMLaunchDiagnostics(String amLaunchDiagnostics);
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java
index 88a89b58543..8aefe9f908d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/rmapp/attempt/RMAppAttemptImpl.java
@@ -73,11 +73,11 @@ import org.apache.hadoop.yarn.server.resourcemanager.amlauncher.AMLauncherEventT
 import org.apache.hadoop.yarn.server.resourcemanager.blacklist.BlacklistManager;
 import org.apache.hadoop.yarn.server.resourcemanager.blacklist.BlacklistUpdates;
 import org.apache.hadoop.yarn.server.resourcemanager.blacklist.DisabledBlacklistManager;
-import org.apache.hadoop.yarn.server.resourcemanager.recovery.records.ApplicationAttemptStateData;
-import org.apache.hadoop.yarn.server.resourcemanager.recovery.records.ApplicationStateData;
 import org.apache.hadoop.yarn.server.resourcemanager.recovery.RMStateStore;
 import org.apache.hadoop.yarn.server.resourcemanager.recovery.RMStateStore.RMState;
 import org.apache.hadoop.yarn.server.resourcemanager.recovery.Recoverable;
+import org.apache.hadoop.yarn.server.resourcemanager.recovery.records.ApplicationAttemptStateData;
+import org.apache.hadoop.yarn.server.resourcemanager.recovery.records.ApplicationStateData;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppEvent;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMAppEventType;
@@ -91,6 +91,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.event.RMAppAt
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainerImpl;
 import org.apache.hadoop.yarn.server.resourcemanager.rmnode.RMNodeFinishedContainersPulledByAMEvent;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.Allocation;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt.AMState;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerNode;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.YarnScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.AppAttemptAddedSchedulerEvent;
@@ -187,6 +188,8 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
   private ResourceRequest amReq = null;
   private BlacklistManager blacklistedNodesForAM = null;
 
+  private String amLaunchDiagnostics;
+
   private static final StateMachineFactory<RMAppAttemptImpl,
                                            RMAppAttemptState,
                                            RMAppAttemptEventType,
@@ -703,8 +706,10 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
   @Override
   public String getDiagnostics() {
     this.readLock.lock();
-
     try {
+      if (diagnostics.length() == 0 && amLaunchDiagnostics != null) {
+        return amLaunchDiagnostics;
+      }
       return this.diagnostics.toString();
     } finally {
       this.readLock.unlock();
@@ -1409,6 +1414,9 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
             appAttempt.launchAMStartTime;
         ClusterMetrics.getMetrics().addAMLaunchDelay(delay);
       }
+
+      appAttempt
+          .updateAMLaunchDiagnostics(AMState.LAUNCHED.getDiagnosticMessage());
       // Register with AMLivelinessMonitor
       appAttempt.attemptLaunched();
 
@@ -1507,6 +1515,9 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
       appAttempt.originalTrackingUrl =
           sanitizeTrackingUrl(registrationEvent.getTrackingurl());
 
+      // reset AMLaunchDiagnostics once AM Registers with RM
+      appAttempt.updateAMLaunchDiagnostics(null);
+
       // Let the app know
       appAttempt.eventHandler.handle(new RMAppEvent(appAttempt
           .getAppAttemptId().getApplicationId(),
@@ -2097,4 +2108,9 @@ public class RMAppAttemptImpl implements RMAppAttempt, Recoverable {
       this.writeLock.unlock();
     }
   }
+
+  @Override
+  public void updateAMLaunchDiagnostics(String amLaunchDiagnostics) {
+    this.amLaunchDiagnostics = amLaunchDiagnostics;
+  }
 }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/SchedulerApplicationAttempt.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/SchedulerApplicationAttempt.java
index c5f8defe921..22c346d8c85 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/SchedulerApplicationAttempt.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/SchedulerApplicationAttempt.java
@@ -19,7 +19,6 @@ package org.apache.hadoop.yarn.server.resourcemanager.scheduler;
 
 import java.util.ArrayList;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -30,6 +29,7 @@ import java.util.Set;
 import java.util.concurrent.atomic.AtomicLong;
 
 import org.apache.commons.lang.time.DateUtils;
+import org.apache.commons.lang.time.FastDateFormat;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience.Private;
@@ -50,6 +50,7 @@ import org.apache.hadoop.yarn.api.records.ResourceRequest;
 import org.apache.hadoop.yarn.nodelabels.CommonNodeLabelsManager;
 import org.apache.hadoop.yarn.server.api.ContainerType;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
+import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.AggregateAppResourceUsage;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttemptState;
@@ -85,6 +86,9 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
   private static final Log LOG = LogFactory
     .getLog(SchedulerApplicationAttempt.class);
 
+  private FastDateFormat fdf =
+      FastDateFormat.getInstance("EEE MMM dd HH:mm:ss Z yyyy");
+
   private static final long MEM_AGGREGATE_ALLOCATION_CACHE_MSECS = 3000;
   protected long lastMemoryAggregateAllocationUpdateTime = 0;
   private long lastMemorySeconds = 0;
@@ -148,10 +152,12 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
   protected Queue queue;
   protected boolean isStopped = false;
 
-  private String appAMNodePartitionName = CommonNodeLabelsManager.NO_LABEL;
+  protected String appAMNodePartitionName = CommonNodeLabelsManager.NO_LABEL;
 
   protected final RMContext rmContext;
-  
+
+  private RMAppAttempt appAttempt;
+
   public SchedulerApplicationAttempt(ApplicationAttemptId applicationAttemptId, 
       String user, Queue queue, ActiveUsersManager activeUsersManager,
       RMContext rmContext) {
@@ -166,9 +172,11 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
     if (rmContext.getRMApps() != null &&
         rmContext.getRMApps()
             .containsKey(applicationAttemptId.getApplicationId())) {
+      RMApp rmApp = rmContext.getRMApps().get(applicationAttemptId.getApplicationId());
       ApplicationSubmissionContext appSubmissionContext =
-          rmContext.getRMApps().get(applicationAttemptId.getApplicationId())
+          rmApp
               .getApplicationSubmissionContext();
+      appAttempt = rmApp.getCurrentAppAttempt();
       if (appSubmissionContext != null) {
         unmanagedAM = appSubmissionContext.getUnmanagedAM();
         this.logAggregationContext =
@@ -489,7 +497,7 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
     ContainerType containerType = ContainerType.TASK;
     // The working knowledge is that masterContainer for AM is null as it
     // itself is the master container.
-    if (isWaitingForAMContainer(getApplicationId())) {
+    if (isWaitingForAMContainer()) {
       containerType = ContainerType.APPLICATION_MASTER;
     }
     try {
@@ -575,13 +583,10 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
     return returnList;
   }
 
-  public boolean isWaitingForAMContainer(ApplicationId applicationId) {
+  public boolean isWaitingForAMContainer() {
     // The working knowledge is that masterContainer for AM is null as it
     // itself is the master container.
-    RMAppAttempt appAttempt =
-        rmContext.getRMApps().get(applicationId).getCurrentAppAttempt();
-    return (appAttempt != null && appAttempt.getMasterContainer() == null
-        && appAttempt.getSubmissionContext().getUnmanagedAM() == false);
+    return (!unmanagedAM && appAttempt.getMasterContainer() == null);
   }
 
   // Blacklist used for user containers
@@ -603,7 +608,7 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
   }
 
   public boolean isBlacklisted(String resourceName) {
-    boolean useAMBlacklist = isWaitingForAMContainer(getApplicationId());
+    boolean useAMBlacklist = isWaitingForAMContainer();
     return this.appSchedulingInfo.isBlacklisted(resourceName, useAMBlacklist);
   }
 
@@ -905,4 +910,71 @@ public class SchedulerApplicationAttempt implements SchedulableEntity {
   public String getAppAMNodePartitionName() {
     return appAMNodePartitionName;
   }
+
+  public void updateAMContainerDiagnostics(AMState state,
+      String diagnosticMessage) {
+    if (!isWaitingForAMContainer()) {
+      return;
+    }
+    StringBuilder diagnosticMessageBldr = new StringBuilder();
+    diagnosticMessageBldr.append("[");
+    diagnosticMessageBldr.append(fdf.format(System.currentTimeMillis()));
+    diagnosticMessageBldr.append("] ");
+    switch (state) {
+    case INACTIVATED:
+      diagnosticMessageBldr.append(state.diagnosticMessage);
+      if (diagnosticMessage != null) {
+        diagnosticMessageBldr.append(diagnosticMessage);
+      }
+      getPendingAppDiagnosticMessage(diagnosticMessageBldr);
+      break;
+    case ACTIVATED:
+      diagnosticMessageBldr.append(state.diagnosticMessage);
+      if (diagnosticMessage != null) {
+        diagnosticMessageBldr.append(diagnosticMessage);
+      }
+      getActivedAppDiagnosticMessage(diagnosticMessageBldr);
+      break;
+    default:
+      // UNMANAGED , ASSIGNED
+      diagnosticMessageBldr.append(state.diagnosticMessage);
+      break;
+    }
+    appAttempt.updateAMLaunchDiagnostics(diagnosticMessageBldr.toString());
+  }
+
+  protected void getPendingAppDiagnosticMessage(
+      StringBuilder diagnosticMessage) {
+    // Give the specific information which might be applicable for the
+    // respective scheduler
+    // like partitionAMResourcelimit,UserAMResourceLimit, queue'AMResourceLimit
+  }
+
+  protected void getActivedAppDiagnosticMessage(
+      StringBuilder diagnosticMessage) {
+    // Give the specific information which might be applicable for the
+    // respective scheduler
+    // queue's resource usage for specific partition
+  }
+
+  public static enum AMState {
+    UNMANAGED("User launched the Application Master, since it's unmanaged. "),
+    INACTIVATED("Application is added to the scheduler and is not yet activated. "),
+    ACTIVATED("Application is Activated, waiting for resources to be assigned for AM. "),
+    ASSIGNED("Scheduler has assigned a container for AM, waiting for AM "
+        + "container to be launched"),
+    LAUNCHED("AM container is launched, waiting for AM container to Register "
+        + "with RM")
+    ;
+
+    private String diagnosticMessage;
+
+    AMState(String diagnosticMessage) {
+      this.diagnosticMessage = diagnosticMessage;
+    }
+
+    public String getDiagnosticMessage() {
+      return diagnosticMessage;
+    }
+  }
 }
\ No newline at end of file
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CSAMContainerLaunchDiagnosticsConstants.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CSAMContainerLaunchDiagnosticsConstants.java
new file mode 100644
index 00000000000..4cc062c5fb7
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CSAMContainerLaunchDiagnosticsConstants.java
@@ -0,0 +1,35 @@
+/**
+ * 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.scheduler.capacity;
+
+/**
+ * diagnostic messages for AMcontainer launching
+ */
+public interface CSAMContainerLaunchDiagnosticsConstants {
+  String SKIP_AM_ALLOCATION_IN_IGNORE_EXCLUSIVE_MODE =
+      "Skipping assigning to Node in Ignore Exclusivity mode. ";
+  String SKIP_AM_ALLOCATION_IN_BLACK_LISTED_NODE =
+      "Skipped scheduling for this Node as its black listed. ";
+  String SKIP_AM_ALLOCATION_DUE_TO_LOCALITY =
+      "Skipping assigning to Node as request locality is not matching. ";
+  String QUEUE_AM_RESOURCE_LIMIT_EXCEED =
+      "Queue's AM resource limit exceeded. ";
+  String USER_AM_RESOURCE_LIMIT_EXCEED = "User's AM resource limit exceeded. ";
+  String LAST_NODE_PROCESSED_MSG =
+      " Last Node which was processed for the application : ";
+}
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java
index 782ed037a42..159c7a59d55 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/CapacityScheduler.java
@@ -960,7 +960,7 @@ public class CapacityScheduler extends
         updateDemandForQueue = (LeafQueue) application.getQueue();
       }
 
-      if (application.isWaitingForAMContainer(application.getApplicationId())) {
+      if (application.isWaitingForAMContainer()) {
         // Allocate is for AM and update AM blacklist for this
         application.updateAMBlacklist(
             blacklistAdditions, blacklistRemovals);
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java
index a89707fb984..f58aba2fce3 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java
@@ -60,6 +60,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceUsage;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedContainerChangeRequest;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt.AMState;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerNode;
@@ -634,7 +635,7 @@ public class LeafQueue extends AbstractCSQueue {
           queueUsage.getAMUsed(partitionName));
 
       if (LOG.isDebugEnabled()) {
-        LOG.debug("application AMResource "
+        LOG.debug("application "+application.getId() +" AMResource "
             + application.getAMResource(partitionName)
             + " maxAMResourcePerQueuePercent " + maxAMResourcePerQueuePercent
             + " amLimit " + amLimit + " lastClusterResource "
@@ -653,6 +654,8 @@ public class LeafQueue extends AbstractCSQueue {
               + " skipping enforcement to allow at least one application"
               + " to start");
         } else {
+          application.updateAMContainerDiagnostics(AMState.INACTIVATED,
+              CSAMContainerLaunchDiagnosticsConstants.QUEUE_AM_RESOURCE_LIMIT_EXCEED);
           LOG.info("Not activating application " + applicationId
               + " as  amIfStarted: " + amIfStarted + " exceeds amLimit: "
               + amLimit);
@@ -685,6 +688,8 @@ public class LeafQueue extends AbstractCSQueue {
               + " low. skipping enforcement to allow at least one application"
               + " to start");
         } else {
+          application.updateAMContainerDiagnostics(AMState.INACTIVATED,
+              CSAMContainerLaunchDiagnosticsConstants.USER_AM_RESOURCE_LIMIT_EXCEED);
           LOG.info("Not activating application " + applicationId
               + " for user: " + user + " as userAmIfStarted: "
               + userAmIfStarted + " exceeds userAmLimit: " + userAMLimit);
@@ -693,6 +698,8 @@ public class LeafQueue extends AbstractCSQueue {
       }
       user.activateApplication();
       orderingPolicy.addSchedulableEntity(application);
+      application.updateAMContainerDiagnostics(AMState.ACTIVATED, null);
+
       queueUsage.incAMUsed(partitionName,
           application.getAMResource(partitionName));
       user.getResourceUsage().incAMUsed(partitionName,
@@ -868,6 +875,8 @@ public class LeafQueue extends AbstractCSQueue {
       // Check user limit
       if (!canAssignToUser(clusterResource, application.getUser(), userLimit,
           application, node.getPartition(), currentResourceLimits)) {
+        application.updateAMContainerDiagnostics(AMState.ACTIVATED,
+            "User capacity has reached its maximum limit.");
         continue;
       }
 
@@ -903,7 +912,9 @@ public class LeafQueue extends AbstractCSQueue {
 
         // Done
         return assignment;
-      } else if (!assignment.getSkipped()) {
+      } else if (assignment.getSkipped()) {
+        application.updateNodeInfoForAMDiagnostics(node);
+      } else {
         // If we don't allocate anything, and it is not skipped by application,
         // we will return to respect FIFO of applications
         return CSAssignment.NULL_ASSIGNMENT;
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/allocator/RegularContainerAllocator.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/allocator/RegularContainerAllocator.java
index 6bd4d17982b..820cccd5b0d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/allocator/RegularContainerAllocator.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/allocator/RegularContainerAllocator.java
@@ -28,12 +28,12 @@ import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.api.records.ResourceRequest;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
 import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.RMNodeLabelsManager;
-import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.NodeType;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerAppUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerUtils;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSAMContainerLaunchDiagnosticsConstants;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSAssignment;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.SchedulingMode;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
@@ -79,6 +79,8 @@ public class RegularContainerAllocator extends AbstractContainerAllocator {
       FiCaSchedulerNode node, SchedulingMode schedulingMode,
       ResourceLimits resourceLimits, Priority priority) {
     if (SchedulerAppUtils.isBlacklisted(application, node, LOG)) {
+      application.updateAppSkipNodeDiagnostics(
+          CSAMContainerLaunchDiagnosticsConstants.SKIP_AM_ALLOCATION_IN_BLACK_LISTED_NODE);
       return ContainerAllocation.APP_SKIPPED;
     }
 
@@ -99,16 +101,14 @@ public class RegularContainerAllocator extends AbstractContainerAllocator {
     // AM container allocation doesn't support non-exclusive allocation to
     // avoid painful of preempt an AM container
     if (schedulingMode == SchedulingMode.IGNORE_PARTITION_EXCLUSIVITY) {
-      RMAppAttempt rmAppAttempt =
-          rmContext.getRMApps().get(application.getApplicationId())
-              .getCurrentAppAttempt();
-      if (rmAppAttempt.getSubmissionContext().getUnmanagedAM() == false
-          && null == rmAppAttempt.getMasterContainer()) {
+      if (application.isWaitingForAMContainer()) {
         if (LOG.isDebugEnabled()) {
           LOG.debug("Skip allocating AM container to app_attempt="
               + application.getApplicationAttemptId()
               + ", don't allow to allocate AM container in non-exclusive mode");
         }
+        application.updateAppSkipNodeDiagnostics(
+            "Skipping assigning to Node in Ignore Exclusivity mode. ");
         return ContainerAllocation.APP_SKIPPED;
       }
     }
@@ -318,6 +318,8 @@ public class RegularContainerAllocator extends AbstractContainerAllocator {
           schedulingMode, currentResoureLimits);
     }
 
+    application.updateAppSkipNodeDiagnostics(
+        CSAMContainerLaunchDiagnosticsConstants.SKIP_AM_ALLOCATION_DUE_TO_LOCALITY);
     return ContainerAllocation.APP_SKIPPED;
   }
 
@@ -621,6 +623,8 @@ public class RegularContainerAllocator extends AbstractContainerAllocator {
 
     // something went wrong getting/creating the container
     if (container == null) {
+      application
+          .updateAppSkipNodeDiagnostics("Scheduling of container failed. ");
       LOG.warn("Couldn't get container for allocation!");
       return ContainerAllocation.APP_SKIPPED;
     }
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/common/fica/FiCaSchedulerApp.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/common/fica/FiCaSchedulerApp.java
index 6f4bfe59610..c9c792e3528 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/common/fica/FiCaSchedulerApp.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/common/fica/FiCaSchedulerApp.java
@@ -34,6 +34,7 @@ import org.apache.hadoop.yarn.api.records.ContainerId;
 import org.apache.hadoop.yarn.api.records.ContainerStatus;
 import org.apache.hadoop.yarn.api.records.NMToken;
 import org.apache.hadoop.yarn.api.records.NodeId;
+import org.apache.hadoop.yarn.api.records.NodeLabel;
 import org.apache.hadoop.yarn.api.records.Priority;
 import org.apache.hadoop.yarn.api.records.Resource;
 import org.apache.hadoop.yarn.api.records.ResourceRequest;
@@ -54,13 +55,15 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.Queue;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSAMContainerLaunchDiagnosticsConstants;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSAssignment;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityHeadroomProvider;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.LeafQueue;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.QueueCapacities;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.SchedulingMode;
-import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.allocator.ContainerAllocator;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.allocator.AbstractContainerAllocator;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.allocator.ContainerAllocator;
 import org.apache.hadoop.yarn.util.resource.DefaultResourceCalculator;
 import org.apache.hadoop.yarn.util.resource.ResourceCalculator;
 import org.apache.hadoop.yarn.util.resource.Resources;
@@ -87,6 +90,11 @@ public class FiCaSchedulerApp extends SchedulerApplicationAttempt {
   
   private AbstractContainerAllocator containerAllocator;
 
+  /**
+   * to hold the message if its app doesn't not get container from a node
+   */
+  private String appSkipNodeDiagnostics;
+
   public FiCaSchedulerApp(ApplicationAttemptId applicationAttemptId, 
       String user, Queue queue, ActiveUsersManager activeUsersManager,
       RMContext rmContext) {
@@ -187,6 +195,8 @@ public class FiCaSchedulerApp extends SchedulerApplicationAttempt {
             node.getNodeID(), appSchedulingInfo.getUser(), this.rmContext,
             request.getNodeLabelExpression());
 
+    updateAMContainerDiagnostics(AMState.ASSIGNED, null);
+
     // Add it to allContainers list.
     newlyAllocatedContainers.add(rmContainer);
     liveContainers.put(container.getId(), rmContainer);    
@@ -502,4 +512,85 @@ public class FiCaSchedulerApp extends SchedulerApplicationAttempt {
       getCSLeafQueue().incAMUsedResource(newPartition, containerResource, this);
     }
   }
+
+  protected void getPendingAppDiagnosticMessage(
+      StringBuilder diagnosticMessage) {
+    LeafQueue queue = getCSLeafQueue();
+    diagnosticMessage.append(" Details : AM Partition = ");
+    diagnosticMessage.append(appAMNodePartitionName.isEmpty()
+        ? NodeLabel.DEFAULT_NODE_LABEL_PARTITION : appAMNodePartitionName);
+    diagnosticMessage.append("; ");
+    diagnosticMessage.append("AM Resource Request = ");
+    diagnosticMessage.append(getAMResource(appAMNodePartitionName));
+    diagnosticMessage.append("; ");
+    diagnosticMessage.append("Queue Resource Limit for AM = ");
+    diagnosticMessage
+        .append(queue.getAMResourceLimitPerPartition(appAMNodePartitionName));
+    diagnosticMessage.append("; ");
+    diagnosticMessage.append("User AM Resource Limit of the queue = ");
+    diagnosticMessage.append(
+        queue.getUserAMResourceLimitPerPartition(appAMNodePartitionName));
+    diagnosticMessage.append("; ");
+    diagnosticMessage.append("Queue AM Resource Usage = ");
+    diagnosticMessage.append(
+        queue.getQueueResourceUsage().getAMUsed(appAMNodePartitionName));
+    diagnosticMessage.append("; ");
+  }
+
+  protected void getActivedAppDiagnosticMessage(
+      StringBuilder diagnosticMessage) {
+    LeafQueue queue = getCSLeafQueue();
+    QueueCapacities queueCapacities = queue.getQueueCapacities();
+    diagnosticMessage.append(" Details : AM Partition = ");
+    diagnosticMessage.append(appAMNodePartitionName.isEmpty()
+        ? NodeLabel.DEFAULT_NODE_LABEL_PARTITION : appAMNodePartitionName);
+    diagnosticMessage.append(" ; ");
+    diagnosticMessage.append("Partition Resource = ");
+    diagnosticMessage.append(rmContext.getNodeLabelManager()
+        .getResourceByLabel(appAMNodePartitionName, Resources.none()));
+    diagnosticMessage.append(" ; ");
+    diagnosticMessage.append("Queue's Absolute capacity = ");
+    diagnosticMessage.append(
+        queueCapacities.getAbsoluteCapacity(appAMNodePartitionName) * 100);
+    diagnosticMessage.append(" % ; ");
+    diagnosticMessage.append("Queue's Absolute used capacity = ");
+    diagnosticMessage.append(
+        queueCapacities.getAbsoluteUsedCapacity(appAMNodePartitionName) * 100);
+    diagnosticMessage.append(" % ; ");
+    diagnosticMessage.append("Queue's Absolute max capacity = ");
+    diagnosticMessage.append(
+        queueCapacities.getAbsoluteMaximumCapacity(appAMNodePartitionName)
+            * 100);
+    diagnosticMessage.append(" % ; ");
+  }
+
+  /**
+   * Set the message temporarily if the reason is known for why scheduling did
+   * not happen for a given node, if not message will be over written
+   * @param message
+   */
+  public void updateAppSkipNodeDiagnostics(String message) {
+    this.appSkipNodeDiagnostics = message;
+  }
+
+  public void updateNodeInfoForAMDiagnostics(FiCaSchedulerNode node) {
+    if (isWaitingForAMContainer()) {
+      StringBuilder diagnosticMessageBldr = new StringBuilder();
+      if (appSkipNodeDiagnostics != null) {
+        diagnosticMessageBldr.append(appSkipNodeDiagnostics);
+        appSkipNodeDiagnostics = null;
+      }
+      diagnosticMessageBldr.append(
+          CSAMContainerLaunchDiagnosticsConstants.LAST_NODE_PROCESSED_MSG);
+      diagnosticMessageBldr.append(node.getNodeID());
+      diagnosticMessageBldr.append(" ( Partition : ");
+      diagnosticMessageBldr.append(node.getLabels());
+      diagnosticMessageBldr.append(", Total resource : ");
+      diagnosticMessageBldr.append(node.getTotalResource());
+      diagnosticMessageBldr.append(", Available resource : ");
+      diagnosticMessageBldr.append(node.getAvailableResource());
+      diagnosticMessageBldr.append(" ).");
+      updateAMContainerDiagnostics(AMState.ACTIVATED, diagnosticMessageBldr.toString());
+    }
+  }
 }
diff --git a/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 b/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
index 04977a66899..9c16e493e15 100644
--- a/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
+++ b/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
@@ -75,9 +75,9 @@ import org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnSched
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ActiveUsersManager;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.Allocation;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.QueueMetrics;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedContainerChangeRequest;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplication;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt;
-import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedContainerChangeRequest;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerUtils;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.QueueEntitlement;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.event.AppAddedSchedulerEvent;
@@ -1008,7 +1008,7 @@ public class FairScheduler extends
         preemptionContainerIds.add(container.getContainerId());
       }
 
-      if (application.isWaitingForAMContainer(application.getApplicationId())) {
+      if (application.isWaitingForAMContainer()) {
         // Allocate is for AM and update AM blacklist for this
         application.updateAMBlacklist(
             blacklistAdditions, blacklistRemovals);
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fifo/FifoScheduler.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fifo/FifoScheduler.java
index cfae3a22e96..8e75d1167d3 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fifo/FifoScheduler.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fifo/FifoScheduler.java
@@ -359,7 +359,7 @@ public class FifoScheduler extends
             " #ask=" + ask.size());
       }
 
-      if (application.isWaitingForAMContainer(application.getApplicationId())) {
+      if (application.isWaitingForAMContainer()) {
         // Allocate is for AM and update AM blacklist for this
         application.updateAMBlacklist(
             blacklistAdditions, blacklistRemovals);
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/reservation/TestCapacitySchedulerPlanFollower.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/reservation/TestCapacitySchedulerPlanFollower.java
index 9152d1207f9..bccd5c34a63 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/reservation/TestCapacitySchedulerPlanFollower.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/reservation/TestCapacitySchedulerPlanFollower.java
@@ -37,6 +37,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
 import org.apache.hadoop.yarn.server.resourcemanager.reservation.exceptions.PlanningException;
 import org.apache.hadoop.yarn.server.resourcemanager.reservation.planning.ReservationAgent;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
+import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.Queue;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CSQueue;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity.CapacityScheduler;
@@ -80,9 +81,12 @@ public class TestCapacitySchedulerPlanFollower extends
     ConcurrentMap<ApplicationId, RMApp> spyApps =
         spy(new ConcurrentHashMap<ApplicationId, RMApp>());
     RMApp rmApp = mock(RMApp.class);
+    RMAppAttempt rmAppAttempt = mock(RMAppAttempt.class);
     when(rmApp.getRMAppAttempt((ApplicationAttemptId) Matchers.any()))
-        .thenReturn(null);
+        .thenReturn(rmAppAttempt);
+    when(rmApp.getCurrentAppAttempt()).thenReturn(rmAppAttempt);
     Mockito.doReturn(rmApp).when(spyApps).get((ApplicationId) Matchers.any());
+    Mockito.doReturn(true).when(spyApps).containsKey((ApplicationId) Matchers.any());
     when(spyRMContext.getRMApps()).thenReturn(spyApps);
     when(spyRMContext.getScheduler()).thenReturn(scheduler);
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimits.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimits.java
index 9f4b9f5daee..3e650132bc2 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimits.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimits.java
@@ -49,6 +49,7 @@ import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
 import org.apache.hadoop.yarn.nodelabels.CommonNodeLabelsManager;
 import org.apache.hadoop.yarn.server.resourcemanager.RMContext;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
+import org.apache.hadoop.yarn.server.resourcemanager.rmapp.attempt.RMAppAttempt;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ActiveUsersManager;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
@@ -602,7 +603,13 @@ public class TestApplicationLimits {
     when(rmApp.getAMResourceRequest()).thenReturn(amResourceRequest);
     Mockito.doReturn(rmApp).when(spyApps).get((ApplicationId)Matchers.any());
     when(spyRMContext.getRMApps()).thenReturn(spyApps);
-    
+    RMAppAttempt rmAppAttempt = mock(RMAppAttempt.class);
+    when(rmApp.getRMAppAttempt((ApplicationAttemptId) Matchers.any()))
+        .thenReturn(rmAppAttempt);
+    when(rmApp.getCurrentAppAttempt()).thenReturn(rmAppAttempt);
+    Mockito.doReturn(rmApp).when(spyApps).get((ApplicationId) Matchers.any());
+    Mockito.doReturn(true).when(spyApps)
+        .containsKey((ApplicationId) Matchers.any());
 
     Priority priority_1 = TestUtils.createMockPriority(1);
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimitsByPartition.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimitsByPartition.java
index 267abaf98ae..89fcb166272 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimitsByPartition.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestApplicationLimitsByPartition.java
@@ -32,6 +32,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.NullRMNodeLabels
 import org.apache.hadoop.yarn.server.resourcemanager.nodelabels.RMNodeLabelsManager;
 import org.apache.hadoop.yarn.server.resourcemanager.rmapp.RMApp;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceScheduler;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt.AMState;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
@@ -120,15 +121,13 @@ public class TestApplicationLimitsByPartition {
 
     // Submit app1 with 1Gb AM resource to Queue A1 for label X
     RMApp app1 = rm1.submitApp(GB, "app", "user", null, "a1", "x");
-    MockRM.launchAndRegisterAM(app1, rm1, nm1);
 
     // Submit app2 with 1Gb AM resource to Queue A1 for label X
     RMApp app2 = rm1.submitApp(GB, "app", "user", null, "a1", "x");
-    MockRM.launchAndRegisterAM(app2, rm1, nm1);
 
     // Submit 3rd app to Queue A1 for label X, and this will be pending as
     // AM limit is already crossed for label X. (2GB)
-    rm1.submitApp(GB, "app", "user", null, "a1", "x");
+    RMApp pendingApp = rm1.submitApp(GB, "app", "user", null, "a1", "x");
 
     CapacityScheduler cs = (CapacityScheduler) rm1.getResourceScheduler();
     LeafQueue leafQueue = (LeafQueue) cs.getQueue("a1");
@@ -138,6 +137,16 @@ public class TestApplicationLimitsByPartition {
     // pending.
     Assert.assertEquals(2, leafQueue.getNumActiveApplications());
     Assert.assertEquals(1, leafQueue.getNumPendingApplications());
+    Assert.assertTrue("AM diagnostics not set properly", app1.getDiagnostics()
+        .toString().contains(AMState.ACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly", app2.getDiagnostics()
+        .toString().contains(AMState.ACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString()
+            .contains(AMState.INACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString().contains(
+            CSAMContainerLaunchDiagnosticsConstants.QUEUE_AM_RESOURCE_LIMIT_EXCEED));
 
     // Now verify the same test case in Queue C1 where label is not configured.
     // Submit an app to Queue C1 with empty label
@@ -150,7 +159,7 @@ public class TestApplicationLimitsByPartition {
 
     // Submit 3rd app to Queue C1. This will be pending as Queue's am-limit
     // is reached.
-    rm1.submitApp(GB, "app", "user", null, "c1");
+    pendingApp = rm1.submitApp(GB, "app", "user", null, "c1");
 
     leafQueue = (LeafQueue) cs.getQueue("c1");
     Assert.assertNotNull(leafQueue);
@@ -159,6 +168,12 @@ public class TestApplicationLimitsByPartition {
     // is reached.
     Assert.assertEquals(2, leafQueue.getNumActiveApplications());
     Assert.assertEquals(1, leafQueue.getNumPendingApplications());
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString()
+            .contains(AMState.INACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString().contains(
+            CSAMContainerLaunchDiagnosticsConstants.QUEUE_AM_RESOURCE_LIMIT_EXCEED));
 
     rm1.killApp(app3.getApplicationId());
     Thread.sleep(1000);
@@ -288,11 +303,10 @@ public class TestApplicationLimitsByPartition {
 
     // Submit app1 (2 GB) to Queue A1 and label X
     RMApp app1 = rm1.submitApp(2 * GB, "app", "user", null, "a1", "x");
-    MockRM.launchAndRegisterAM(app1, rm1, nm1);
 
     // Submit 2nd app to label "X" with one GB. Since queue am-limit is 2GB,
     // 2nd app will be pending and first one will get activated.
-    rm1.submitApp(GB, "app", "user", null, "a1", "x");
+    RMApp pendingApp = rm1.submitApp(GB, "app", "user", null, "a1", "x");
 
     CapacityScheduler cs = (CapacityScheduler) rm1.getResourceScheduler();
     LeafQueue leafQueue = (LeafQueue) cs.getQueue("a1");
@@ -302,6 +316,14 @@ public class TestApplicationLimitsByPartition {
     // used for partition "x" also.
     Assert.assertEquals(1, leafQueue.getNumActiveApplications());
     Assert.assertEquals(1, leafQueue.getNumPendingApplications());
+    Assert.assertTrue("AM diagnostics not set properly", app1.getDiagnostics()
+        .toString().contains(AMState.ACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString()
+            .contains(AMState.INACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString()
+            .contains(CSAMContainerLaunchDiagnosticsConstants.QUEUE_AM_RESOURCE_LIMIT_EXCEED));
     rm1.close();
   }
 
@@ -381,7 +403,7 @@ public class TestApplicationLimitsByPartition {
     // 4Gb -> 40% of label "X" in queue A1
     // Since we have 2 users, 50% of 4Gb will be max for each user. Here user1
     // has already crossed this 2GB limit, hence this app will be pending.
-    rm1.submitApp(GB, "app", user_1, null, "a1", "x");
+    RMApp pendingApp = rm1.submitApp(GB, "app", user_1, null, "a1", "x");
 
     // Verify active applications count per user and also in queue level.
     Assert.assertEquals(3, leafQueue.getNumActiveApplications());
@@ -389,6 +411,14 @@ public class TestApplicationLimitsByPartition {
     Assert.assertEquals(2, leafQueue.getNumActiveApplications(user_1));
     Assert.assertEquals(1, leafQueue.getNumPendingApplications(user_1));
     Assert.assertEquals(1, leafQueue.getNumPendingApplications());
+
+    //verify Diagnostic messages
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString()
+            .contains(AMState.INACTIVATED.getDiagnosticMessage()));
+    Assert.assertTrue("AM diagnostics not set properly",
+        pendingApp.getDiagnostics().toString().contains(
+            CSAMContainerLaunchDiagnosticsConstants.USER_AM_RESOURCE_LIMIT_EXCEED));
     rm1.close();
   }
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestNodeLabelContainerAllocation.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestNodeLabelContainerAllocation.java
index 91666df1a4d..dff82ca5b47 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestNodeLabelContainerAllocation.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestNodeLabelContainerAllocation.java
@@ -1028,10 +1028,11 @@ public class TestNodeLabelContainerAllocation {
 
     rm1.getRMContext().setNodeLabelManager(mgr);
     rm1.start();
-    MockNM nm1 = rm1.registerNode("h1:1234", 8 * GB); // label = x
+    String nodeIdStr = "h1:1234";
+    MockNM nm1 = rm1.registerNode(nodeIdStr, 8 * GB); // label = x
 
     // launch an app to queue b1 (label = y), AM container should be launched in nm3
-    rm1.submitApp(1 * GB, "app", "user", null, "b1");
+    RMApp app = rm1.submitApp(1 * GB, "app", "user", null, "b1");
    
     CapacityScheduler cs = (CapacityScheduler) rm1.getResourceScheduler();
     RMNode rmNode1 = rm1.getRMContext().getRMNodes().get(nm1.getNodeId());
@@ -1040,7 +1041,17 @@ public class TestNodeLabelContainerAllocation {
     for (int i = 0; i < 50; i++) {
       cs.handle(new NodeUpdateSchedulerEvent(rmNode1));
     }
-    
+
+    Assert.assertTrue(
+        "Scheduler diagnostics should have reason for not assigning the node",
+        app.getDiagnostics().toString().contains(
+            CSAMContainerLaunchDiagnosticsConstants.SKIP_AM_ALLOCATION_IN_IGNORE_EXCLUSIVE_MODE));
+
+    Assert.assertTrue(
+        "Scheduler diagnostics should have last processed node information",
+        app.getDiagnostics().toString().contains(
+            CSAMContainerLaunchDiagnosticsConstants.LAST_NODE_PROCESSED_MSG
+                + nodeIdStr + " ( Partition : [x]"));
     Assert.assertEquals(0, cs.getSchedulerNode(nm1.getNodeId())
         .getNumContainers());
     
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestReservations.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestReservations.java
index 884de2aed81..49de4787aae 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestReservations.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestReservations.java
@@ -21,6 +21,7 @@ package org.apache.hadoop.yarn.server.resourcemanager.scheduler.capacity;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.when;
@@ -53,6 +54,7 @@ import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainer;
 import org.apache.hadoop.yarn.server.resourcemanager.rmcontainer.RMContainerImpl;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ActiveUsersManager;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.ResourceLimits;
+import org.apache.hadoop.yarn.server.resourcemanager.scheduler.SchedulerApplicationAttempt.AMState;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerApp;
 import org.apache.hadoop.yarn.server.resourcemanager.scheduler.common.fica.FiCaSchedulerNode;
 import org.apache.hadoop.yarn.server.resourcemanager.security.RMContainerTokenSecretManager;
@@ -65,6 +67,7 @@ import org.apache.log4j.LogManager;
 import org.apache.log4j.Logger;
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.Mockito;
 
 public class TestReservations {
 
@@ -188,6 +191,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
 
     a.submitApplicationAttempt(app_0, user_0); 
@@ -196,6 +202,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
@@ -348,6 +357,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
 
     a.submitApplicationAttempt(app_0, user_0); 
@@ -356,6 +368,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
@@ -502,6 +517,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
 
     a.submitApplicationAttempt(app_0, user_0); 
@@ -510,6 +528,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
@@ -758,6 +779,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
 
     a.submitApplicationAttempt(app_0, user_0); 
@@ -766,6 +790,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
@@ -927,6 +954,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
     a.submitApplicationAttempt(app_0, user_0); 
 
@@ -934,6 +964,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
@@ -1068,6 +1101,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(0, 0);
     FiCaSchedulerApp app_0 = new FiCaSchedulerApp(appAttemptId_0, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_0 = spy(app_0);
+    Mockito.doNothing().when(app_0).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     rmContext.getRMApps().put(app_0.getApplicationId(), mock(RMApp.class));
 
     a.submitApplicationAttempt(app_0, user_0); 
@@ -1076,6 +1112,9 @@ public class TestReservations {
         .getMockApplicationAttemptId(1, 0);
     FiCaSchedulerApp app_1 = new FiCaSchedulerApp(appAttemptId_1, user_0, a,
         mock(ActiveUsersManager.class), spyRMContext);
+    app_1 = spy(app_1);
+    Mockito.doNothing().when(app_1).updateAMContainerDiagnostics(any(AMState.class),
+        any(String.class));
     a.submitApplicationAttempt(app_1, user_0); 
 
     // Setup some nodes
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/TestRMWebServicesApps.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/TestRMWebServicesApps.java
index d7e80e86590..d0a8c27e528 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/TestRMWebServicesApps.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/webapp/TestRMWebServicesApps.java
@@ -1387,8 +1387,8 @@ public class TestRMWebServicesApps extends JerseyTestBase {
     assertEquals("progress doesn't match", 0, progress, 0.0);
     WebServicesTestUtils.checkStringMatch("trackingUI", "UNASSIGNED",
         trackingUI);
-    WebServicesTestUtils.checkStringMatch("diagnostics", app.getDiagnostics()
-        .toString(), diagnostics);
+    WebServicesTestUtils.checkStringEqual("diagnostics",
+        app.getDiagnostics().toString(), diagnostics);
     assertEquals("clusterId doesn't match",
         ResourceManager.getClusterTimeStamp(), clusterId);
     assertEquals("startedTime doesn't match", app.getStartTime(), startedTime);