diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/metrics/NodeManagerMetrics.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/metrics/NodeManagerMetrics.java
index f0abfd4ff75..1e7149bf1a6 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/metrics/NodeManagerMetrics.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/metrics/NodeManagerMetrics.java
@@ -211,7 +211,7 @@ public void completeOpportunisticContainer(Resource res) {
 
   public void addResource(Resource res) {
     availableMB = availableMB + res.getMemorySize();
-    availableGB.incr((int)Math.floor(availableMB/1024d));
+    availableGB.set((int)Math.floor(availableMB/1024d));
     availableVCores.incr(res.getVirtualCores());
   }
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/metrics/TestNodeManagerMetrics.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/metrics/TestNodeManagerMetrics.java
index a08ee82e759..6a6279a241a 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/metrics/TestNodeManagerMetrics.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/metrics/TestNodeManagerMetrics.java
@@ -86,6 +86,22 @@
     checkMetrics(10, 1, 1, 1, 1, 1, 4, 7, 4, 13, 3);
   }
 
+  @Test
+  public void testAddResource(){
+    DefaultMetricsSystem.initialize("NodeManager");
+    NodeManagerMetrics metrics = NodeManagerMetrics.create();
+    Resource total = Records.newRecord(Resource.class);
+    total.setMemorySize(8*GiB);
+    total.setVirtualCores(16);
+    metrics.addResource(total);
+    MetricsRecordBuilder rb = getMetrics("NodeManagerMetrics");
+    assertGauge("AvailableGB", 8, rb);
+    // Update resource
+    metrics.addResource(total);
+    rb = getMetrics("NodeManagerMetrics");
+    assertGauge("AvailableGB", 16, rb);
+  }
+
   private void checkMetrics(int launched, int completed, int failed, int killed,
       int initing, int running, int allocatedGB,
       int allocatedContainers, int availableGB, int allocatedVCores,