From 83fd33d5fe847b1daa2d8e8e98329484a02078f3 Mon Sep 17 00:00:00 2001
From: Junping Du <junping_du@apache.org>
Date: Thu, 21 Jan 2016 10:52:15 -0800
Subject: [PATCH] YARN-4623.
 TestSystemMetricsPublisher#testPublishAppAttemptMetricsForUnmanagedAM fails
 with NPE on branch-2.7. Contributed by Naganarasimha G R.

---
 hadoop-yarn-project/CHANGES.txt                               | 3 +++
 .../resourcemanager/metrics/SystemMetricsPublisher.java       | 4 +++-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index 0f869e20ab7..0b6b5ae42a6 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -72,6 +72,9 @@ Release 2.7.3 - UNRELEASED
     YARN-4610. Reservations continue looking for one app causes other apps to
     starve (jlowe)
 
+    YARN-4623. TestSystemMetricsPublisher#testPublishAppAttemptMetricsForUnmanagedAM
+    fails with NPE on branch-2.7. (Naganarasimha G R via junping_du)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/SystemMetricsPublisher.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/SystemMetricsPublisher.java
index fbb4a8a50e2..5cb8a3c1a90 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/SystemMetricsPublisher.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/metrics/SystemMetricsPublisher.java
@@ -160,6 +160,8 @@ public class SystemMetricsPublisher extends CompositeService {
   public void appAttemptFinished(RMAppAttempt appAttempt,
       RMAppAttemptState appAttemtpState, RMApp app, long finishedTime) {
     if (publishSystemMetrics) {
+      ContainerId container = (appAttempt.getMasterContainer() == null) ? null
+          : appAttempt.getMasterContainer().getId();
       dispatcher.getEventHandler().handle(
           new AppAttemptFinishedEvent(
               appAttempt.getAppAttemptId(),
@@ -171,7 +173,7 @@ public class SystemMetricsPublisher extends CompositeService {
               app.getFinalApplicationStatus(),
               RMServerUtils.createApplicationAttemptState(appAttemtpState),
               finishedTime,
-              appAttempt.getMasterContainer().getId()));
+              container));
     }
   }