diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 8261b34d17..55284da2f9 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -736,6 +736,9 @@ Release 2.7.3 - UNRELEASED
     MAPREDUCE-6554. MRAppMaster servicestart failing with NPE in
     MRAppMaster#parsePreviousJobHistory (Bibin A Chundatt via jlowe)
 
+    MAPREDUCE-6618. YarnClientProtocolProvider leaking the YarnClient thread.
+    (Xuan Gong via jlowe)
+
 Release 2.7.2 - 2016-01-25
 
   INCOMPATIBLE CHANGES
@@ -1041,6 +1044,9 @@ Release 2.6.4 - UNRELEASED
     MAPREDUCE-6554. MRAppMaster servicestart failing with NPE in
     MRAppMaster#parsePreviousJobHistory (Bibin A Chundatt via jlowe)
 
+    MAPREDUCE-6618. YarnClientProtocolProvider leaking the YarnClient thread.
+    (Xuan Gong via jlowe)
+
 Release 2.6.3 - 2015-12-17
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientCache.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientCache.java
index 4335c82296..93ea5c437c 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientCache.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientCache.java
@@ -22,11 +22,11 @@
 import java.security.PrivilegedAction;
 import java.util.HashMap;
 import java.util.Map;
-
 import org.apache.commons.lang.StringUtils;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.mapreduce.JobID;
 import org.apache.hadoop.mapreduce.v2.api.HSClientProtocol;
 import org.apache.hadoop.mapreduce.v2.api.MRClientProtocol;
@@ -97,4 +97,26 @@ public MRClientProtocol run() {
       }
     });
   }
+
+  public void close() throws IOException {
+    if (rm != null) {
+      rm.close();
+    }
+
+    if (hsProxy != null) {
+      RPC.stopProxy(hsProxy);
+      hsProxy = null;
+    }
+
+    if (cache != null && !cache.isEmpty()) {
+      for (ClientServiceDelegate delegate : cache.values()) {
+        if (delegate != null) {
+          delegate.close();
+          delegate = null;
+        }
+      }
+      cache.clear();
+      cache = null;
+    }
+  }
 }
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientServiceDelegate.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientServiceDelegate.java
index 8517c19737..eac8dbc0ae 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientServiceDelegate.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/ClientServiceDelegate.java
@@ -33,6 +33,7 @@
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeysPublic;
+import org.apache.hadoop.ipc.RPC;
 import org.apache.hadoop.mapreduce.JobID;
 import org.apache.hadoop.mapreduce.JobStatus;
 import org.apache.hadoop.mapreduce.MRJobConfig;
@@ -532,4 +533,19 @@ public LogParams getLogFilePath(JobID oldJobID, TaskAttemptID oldTaskAttemptID)
       throw new IOException("Cannot get log path for a in-progress job");
     }
   }
+
+  public void close() throws IOException {
+    if (rm != null) {
+      rm.close();
+    }
+
+    if (historyServerProxy != null) {
+      RPC.stopProxy(historyServerProxy);
+    }
+
+    if (realProxy != null) {
+      RPC.stopProxy(realProxy);
+      realProxy = null;
+    }
+  }
 }
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YARNRunner.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YARNRunner.java
index fe631de99a..1342282784 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YARNRunner.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YARNRunner.java
@@ -756,4 +756,15 @@ private static void warnForJavaLibPath(String opts, String component,
                envConf + " config settings.");
     }
   }
+
+  public void close() throws IOException {
+    if (resMgrDelegate != null) {
+      resMgrDelegate.close();
+      resMgrDelegate = null;
+    }
+    if (clientCache != null) {
+      clientCache.close();
+      clientCache = null;
+    }
+  }
 }
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YarnClientProtocolProvider.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YarnClientProtocolProvider.java
index 29d3f66cc3..6583fa29ad 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YarnClientProtocolProvider.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/main/java/org/apache/hadoop/mapred/YarnClientProtocolProvider.java
@@ -44,7 +44,8 @@ public ClientProtocol create(InetSocketAddress addr, Configuration conf)
 
   @Override
   public void close(ClientProtocol clientProtocol) throws IOException {
-    // nothing to do
+    if (clientProtocol instanceof YARNRunner) {
+      ((YARNRunner)clientProtocol).close();
+    }
   }
-
 }
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/TestYarnClientProtocolProvider.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/TestYarnClientProtocolProvider.java
index aeb20cd449..4d84fa9e10 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/TestYarnClientProtocolProvider.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapreduce/TestYarnClientProtocolProvider.java
@@ -21,10 +21,11 @@
 import static org.mockito.Matchers.any;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.doNothing;
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
-
 import junit.framework.TestCase;
 
 import org.apache.hadoop.conf.Configuration;
@@ -113,6 +114,8 @@ public void testClusterGetDelegationToken() throws Exception {
         @Override
         protected void serviceStart() throws Exception {
           assertTrue(this.client instanceof YarnClientImpl);
+          this.client = spy(this.client);
+          doNothing().when(this.client).close();
           ((YarnClientImpl) this.client).setRMClient(cRMProtocol);
         }
       };
@@ -126,5 +129,4 @@ protected void serviceStart() throws Exception {
       }
     }
   }
-
 }