diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 901aa9b0f5..d0eaa60a73 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -335,6 +335,9 @@ Release 0.23.3 - UNRELEASED
     MAPREDUCE-4128. AM Recovery expects all attempts of a completed task to
     also be completed. (Bikas Saha via bobby)
 
+    MAPREDUCE-4144. Fix a NPE in the ResourceManager when handling node
+    updates. (Jason Lowe via sseth)
+
 Release 0.23.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-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-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java
index c171fa1e2b..2256799f9b 100644
--- a/hadoop-mapreduce-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-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/LeafQueue.java
@@ -1118,13 +1118,12 @@ private Resource assignOffSwitchContainers(Resource clusterResource, SchedulerNo
   boolean canAssign(SchedulerApp application, Priority priority, 
       SchedulerNode node, NodeType type, RMContainer reservedContainer) {
 
-    // Reserved... 
-    if (reservedContainer != null) {
-      return true;
-    }
-    
     // Clearly we need containers for this application...
     if (type == NodeType.OFF_SWITCH) {
+      if (reservedContainer != null) {
+        return true;
+      }
+
       // 'Delay' off-switch
       ResourceRequest offSwitchRequest = 
           application.getResourceRequest(priority, RMNode.ANY);
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestLeafQueue.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestLeafQueue.java
index 29aaaa4761..8be9b20193 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestLeafQueue.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/test/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/capacity/TestLeafQueue.java
@@ -926,6 +926,103 @@ public void testReservation() throws Exception {
     assertEquals(4*GB, a.getMetrics().getAllocatedMB());
   }
   
+  @Test
+  public void testStolenReservedContainer() throws Exception {
+    // Manipulate queue 'a'
+    LeafQueue a = stubLeafQueue((LeafQueue)queues.get(A));
+    //unset maxCapacity
+    a.setMaxCapacity(1.0f);
+
+    // Users
+    final String user_0 = "user_0";
+    final String user_1 = "user_1";
+
+    // Submit applications
+    final ApplicationAttemptId appAttemptId_0 =
+        TestUtils.getMockApplicationAttemptId(0, 0);
+    SchedulerApp app_0 =
+        new SchedulerApp(appAttemptId_0, user_0, a,
+            mock(ActiveUsersManager.class), rmContext, null);
+    a.submitApplication(app_0, user_0, A);
+
+    final ApplicationAttemptId appAttemptId_1 =
+        TestUtils.getMockApplicationAttemptId(1, 0);
+    SchedulerApp app_1 =
+        new SchedulerApp(appAttemptId_1, user_1, a,
+            mock(ActiveUsersManager.class), rmContext, null);
+    a.submitApplication(app_1, user_1, A);
+
+    // Setup some nodes
+    String host_0 = "host_0";
+    SchedulerNode node_0 = TestUtils.getMockNode(host_0, DEFAULT_RACK, 0, 4*GB);
+    String host_1 = "host_1";
+    SchedulerNode node_1 = TestUtils.getMockNode(host_1, DEFAULT_RACK, 0, 4*GB);
+
+    final int numNodes = 3;
+    Resource clusterResource = Resources.createResource(numNodes * (4*GB));
+    when(csContext.getNumClusterNodes()).thenReturn(numNodes);
+
+    // Setup resource-requests
+    Priority priority = TestUtils.createMockPriority(1);
+    app_0.updateResourceRequests(Collections.singletonList(
+            TestUtils.createResourceRequest(RMNodeImpl.ANY, 2*GB, 1, priority,
+                recordFactory)));
+
+    // Setup app_1 to request a 4GB container on host_0 and
+    // another 4GB container anywhere.
+    ArrayList<ResourceRequest> appRequests_1 =
+        new ArrayList<ResourceRequest>(4);
+    appRequests_1.add(TestUtils.createResourceRequest(host_0, 4*GB, 1,
+        priority, recordFactory));
+    appRequests_1.add(TestUtils.createResourceRequest(DEFAULT_RACK, 4*GB, 1,
+        priority, recordFactory));
+    appRequests_1.add(TestUtils.createResourceRequest(RMNodeImpl.ANY, 4*GB, 2,
+        priority, recordFactory));
+    app_1.updateResourceRequests(appRequests_1);
+
+    // Start testing...
+
+    a.assignContainers(clusterResource, node_0);
+    assertEquals(2*GB, a.getUsedResources().getMemory());
+    assertEquals(2*GB, app_0.getCurrentConsumption().getMemory());
+    assertEquals(0*GB, app_1.getCurrentConsumption().getMemory());
+    assertEquals(0*GB, a.getMetrics().getReservedMB());
+    assertEquals(2*GB, a.getMetrics().getAllocatedMB());
+    assertEquals(0*GB, a.getMetrics().getAvailableMB());
+
+    // Now, reservation should kick in for app_1
+    a.assignContainers(clusterResource, node_0);
+    assertEquals(6*GB, a.getUsedResources().getMemory());
+    assertEquals(2*GB, app_0.getCurrentConsumption().getMemory());
+    assertEquals(0*GB, app_1.getCurrentConsumption().getMemory());
+    assertEquals(4*GB, app_1.getCurrentReservation().getMemory());
+    assertEquals(2*GB, node_0.getUsedResource().getMemory());
+    assertEquals(4*GB, a.getMetrics().getReservedMB());
+    assertEquals(2*GB, a.getMetrics().getAllocatedMB());
+
+    // node_1 heartbeats in and gets the DEFAULT_RACK request for app_1
+    a.assignContainers(clusterResource, node_1);
+    assertEquals(10*GB, a.getUsedResources().getMemory());
+    assertEquals(2*GB, app_0.getCurrentConsumption().getMemory());
+    assertEquals(4*GB, app_1.getCurrentConsumption().getMemory());
+    assertEquals(4*GB, app_1.getCurrentReservation().getMemory());
+    assertEquals(4*GB, node_1.getUsedResource().getMemory());
+    assertEquals(4*GB, a.getMetrics().getReservedMB());
+    assertEquals(6*GB, a.getMetrics().getAllocatedMB());
+
+    // Now free 1 container from app_0 and try to assign to node_0
+    a.completedContainer(clusterResource, app_0, node_0,
+        app_0.getLiveContainers().iterator().next(), null, RMContainerEventType.KILL);
+    a.assignContainers(clusterResource, node_0);
+    assertEquals(8*GB, a.getUsedResources().getMemory());
+    assertEquals(0*GB, app_0.getCurrentConsumption().getMemory());
+    assertEquals(8*GB, app_1.getCurrentConsumption().getMemory());
+    assertEquals(0*GB, app_1.getCurrentReservation().getMemory());
+    assertEquals(4*GB, node_0.getUsedResource().getMemory());
+    assertEquals(0*GB, a.getMetrics().getReservedMB());
+    assertEquals(8*GB, a.getMetrics().getAllocatedMB());
+  }
+
   @Test
   public void testReservationExchange() throws Exception {