diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 88c844a4f1..f9f2db3a94 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -85,6 +85,8 @@ Trunk (unreleased changes)
 
     HADOOP-7968. Errant println left in RPC.getHighestSupportedProtocol (Sho Shimauchi via harsh)
 
+    HADOOP-7987. Support setting the run-as user in unsecure mode. (jitendra)
+
   BUGS
 
     HADOOP-7851. Configuration.getClasses() never returns the default value. 
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
index 7c7e975193..d595b5a802 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java
@@ -80,6 +80,7 @@ public class UserGroupInformation {
    * Percentage of the ticket window to use before we renew ticket.
    */
   private static final float TICKET_RENEW_WINDOW = 0.80f;
+  static final String HADOOP_USER_NAME = "HADOOP_USER_NAME";
   
   /** 
    * UgiMetrics maintains UGI activity statistics
@@ -137,7 +138,16 @@ public boolean commit() throws LoginException {
           LOG.debug("using kerberos user:"+user);
         }
       }
-      // if we don't have a kerberos user, use the OS user
+      //If we don't have a kerberos user and security is disabled, check
+      //if user is specified in the environment or properties
+      if (!isSecurityEnabled() && (user == null)) {
+        String envUser = System.getenv(HADOOP_USER_NAME);
+        if (envUser == null) {
+          envUser = System.getProperty(HADOOP_USER_NAME);
+        }
+        user = envUser == null ? null : new User(envUser);
+      }
+      // use the OS user
       if (user == null) {
         user = getCanonicalUser(OS_PRINCIPAL_CLASS);
         if (LOG.isDebugEnabled()) {
diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/TestUserFromEnv.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/TestUserFromEnv.java
new file mode 100644
index 0000000000..e436f26a07
--- /dev/null
+++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/security/TestUserFromEnv.java
@@ -0,0 +1,32 @@
+/**
+ * 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.security;
+
+import java.io.IOException;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class TestUserFromEnv {
+
+  @Test
+  public void testUserFromEnvironment() throws IOException {
+    System.setProperty(UserGroupInformation.HADOOP_USER_NAME, "randomUser");
+    Assert.assertEquals("randomUser", UserGroupInformation.getLoginUser()
+        .getUserName());
+  }
+}