From c17cd4f7c163cf97d6e42865df25709f29d39e3d Mon Sep 17 00:00:00 2001
From: Vinayakumar B <vinayakumarb@apache.org>
Date: Mon, 20 Apr 2015 14:58:04 +0530
Subject: [PATCH] HDFS-8173. NPE thrown at DataNode shutdown when HTTP server
 was not able to create (Contributed by surendra singh lilhore)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt            |  3 +++
 .../apache/hadoop/hdfs/server/datanode/DataNode.java   | 10 ++++++----
 2 files changed, 9 insertions(+), 4 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 9bb1fd42a7d..8dec32e4b2d 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -526,6 +526,9 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-8043. NPE in MiniDFSCluster teardown. (Brahma Reddy Battula via ozawa)
 
+    HDFS-8173. NPE thrown at DataNode shutdown when HTTP server was not able to
+    create (surendra singh lilhore via vinayakumarb)
+
 Release 2.7.1 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
index 0ddb99c2766..e81da521ac6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java
@@ -1721,10 +1721,12 @@ public class DataNode extends ReconfigurableBase
         LOG.warn("Exception shutting down DataNode", e);
       }
     }
-    try {
-      httpServer.close();
-    } catch (Exception e) {
-      LOG.warn("Exception shutting down DataNode HttpServer", e);
+    if (httpServer != null) {
+      try {
+        httpServer.close();
+      } catch (Exception e) {
+        LOG.warn("Exception shutting down DataNode HttpServer", e);
+      }
     }
 
     if (pauseMonitor != null) {