diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index e6e2ad8cdcf..b39933f1ebf 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -1641,6 +1641,10 @@ Release 0.23.0 - Unreleased
 
     MAPREDUCE-3189. Add link decoration back to MR2's CSS. (Todd Lipcon via
     mahadev)
+    
+    MAPREDUCE-3101. Changed default value of yarn.resourcemanager.acl.enable
+    to true and added some more documentation. (acmurthy) 
+
 Release 0.22.0 - Unreleased
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
index 23be2a0d50d..aec4e194d2d 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-common/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
@@ -129,7 +129,7 @@ public class YarnConfiguration extends Configuration {
   /** Are RM acls enabled.*/
   public static final String RM_ACL_ENABLE = 
     RM_PREFIX + "acl.enable";
-  public static final boolean DEFAULT_RM_ACL_ENABLE = false;
+  public static final boolean DEFAULT_RM_ACL_ENABLE = true;
   
   /** ACL of who can be admin of RM.*/
   public static final String RM_ADMIN_ACL = 
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/resources/yarn-default.xml b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/resources/yarn-default.xml
index 05e979da4c4..806d31cbab6 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/resources/yarn-default.xml
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-common/src/main/resources/yarn-default.xml
@@ -85,7 +85,7 @@
   <property>
     <description>Are RM acls enabled.</description>
     <name>yarn.resourcemanager.acl.enable</name>
-    <value>false</value>
+    <value>true</value>
   </property>
 
   <property>
diff --git a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/ClusterSetup.apt.vm b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/ClusterSetup.apt.vm
index 874abf0fc18..73c856a8d94 100644
--- a/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/ClusterSetup.apt.vm
+++ b/hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/ClusterSetup.apt.vm
@@ -194,17 +194,28 @@ Hadoop MapReduce Next Generation - Cluster Setup
 | | <<<ResourceManager>>> host:port for NodeManagers. | |
 | | | <host:port> |
 *-------------------------+-------------------------+------------------------+
+| <<<yarn.resourcemanager.admin.address>>> | | | 
+| | <<<ResourceManager>>> host:port for administrative commands. | |
+| | | <host:port> |
+*-------------------------+-------------------------+------------------------+
+| <<<yarn.resourcemanager.webapp.address>>> | | | 
+| | <<<ResourceManager>>> web-ui host:port. | |
+| | | <host:port> |
+*-------------------------+-------------------------+------------------------+
 | <<<yarn.resourcemanager.scheduler.class>>> | | |
 | | <<<ResourceManager>>> Scheduler class. | |
 | | | <<<CapacityScheduler>>> (recommended) or <<<FifoScheduler>>> |
 *-------------------------+-------------------------+------------------------+
 | <<<yarn.resourcemanager.acl.enable>>> | | |
 | | <<<true>>> / <<<false>>> | |
-| | | Enable ACLs? |
+| | | Enable ACLs? Defaults to <true>. |
 *-------------------------+-------------------------+------------------------+
 | <<<yarn.resourcemanager.admin.acl>>> | | |
 | | Admin ACL | |
 | | | ACL to set admins on the cluster. |
+| | | ACLs are of for <comma-separated-users><space><comma-separated-groups>. |
+| | | Defaults to special value of <<*>> which means <anyone>. |
+| | | Special value of just <space> means no one has access. |
 *-------------------------+-------------------------+------------------------+
 | <<<yarn.nodemanager.remote-app-log-dir>>> | | |
 | | </logs> | |