diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index 36d304c7876..871829ac369 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -157,6 +157,9 @@ Release 2.6.0 - UNRELEASED
     YARN-1326. RM should log using RMStore at startup time. 
     (Tsuyoshi Ozawa via kasha)
 
+    YARN-2182. Updated ContainerId#toString() to append RM Epoch number.
+    (Tsuyoshi OZAWA via jianhe)
+
   OPTIMIZATIONS
 
   BUG FIXES
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/ContainerId.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/ContainerId.java
index 73e80859049..fc7f40488ec 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/ContainerId.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/api/records/ContainerId.java
@@ -83,7 +83,7 @@ public abstract class ContainerId implements Comparable<ContainerId>{
  
   
   // TODO: fail the app submission if attempts are more than 10 or something
-  private static final ThreadLocal<NumberFormat> appAttemptIdFormat =
+  private static final ThreadLocal<NumberFormat> appAttemptIdAndEpochFormat =
       new ThreadLocal<NumberFormat>() {
         @Override
         public NumberFormat initialValue() {
@@ -153,9 +153,13 @@ public abstract class ContainerId implements Comparable<ContainerId>{
     sb.append(ApplicationId.appIdFormat.get().format(appId.getId()))
         .append("_");
     sb.append(
-        appAttemptIdFormat.get().format(
+        appAttemptIdAndEpochFormat.get().format(
             getApplicationAttemptId().getAttemptId())).append("_");
-    sb.append(containerIdFormat.get().format(getId()));
+    sb.append(containerIdFormat.get().format(0x3fffff & getId()));
+    int epoch = getId() >> 22;
+    if (epoch > 0) {
+      sb.append("_").append(appAttemptIdAndEpochFormat.get().format(epoch));
+    }
     return sb.toString();
   }
 
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/TestContainerId.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/TestContainerId.java
index f92df8a8d0c..b23d0ed3fbc 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/TestContainerId.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/test/java/org/apache/hadoop/yarn/api/TestContainerId.java
@@ -54,7 +54,9 @@ public class TestContainerId {
     long ts = System.currentTimeMillis();
     ContainerId c6 = newContainerId(36473, 4365472, ts, 25645811);
     Assert.assertEquals("container_10_0001_01_000001", c1.toString());
-    Assert.assertEquals("container_" + ts + "_36473_4365472_25645811",
+    Assert.assertEquals(479987, 0x003fffff & c6.getId());
+    Assert.assertEquals(6, c6.getId() >> 22);
+    Assert.assertEquals("container_" + ts + "_36473_4365472_479987_06",
         c6.toString());
   }