From 9b959f3ee70cfdaf532d72f0bbbd1a4be0be12aa Mon Sep 17 00:00:00 2001
From: Arpit Agarwal <arp@apache.org>
Date: Thu, 11 Feb 2016 20:40:03 -0800
Subject: [PATCH] HDFS-9790. HDFS Balancer should exit with a proper message if
 upgrade is not finalized (Contributed by Xiaobing Zhou)

---
 hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt                    | 3 +++
 .../java/org/apache/hadoop/hdfs/server/balancer/Balancer.java  | 2 ++
 2 files changed, 5 insertions(+)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 73a09d6627a..c0d7113b771 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -2739,6 +2739,9 @@ Release 2.8.0 - UNRELEASED
 
     HDFS-9788. Incompatible tag renumbering in HeartbeatResponseProto. (wang)
 
+    HDFS-9790. HDFS Balancer should exit with a proper message if upgrade is
+    not finalized. (Xiaobing Zhou via Arpit Agarwal)
+
 Release 2.7.3 - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
index 927fb7fbcc9..191e1c3d4f6 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/balancer/Balancer.java
@@ -586,6 +586,8 @@ public class Balancer {
       // Should not run the balancer during an unfinalized upgrade, since moved
       // blocks are not deleted on the source datanode.
       if (!runDuringUpgrade && nnc.isUpgrading()) {
+        System.err.println("Balancer exiting as upgrade is not finalized, "
+            + "please finalize the HDFS upgrade before running the balancer.");
         return newResult(ExitStatus.UNFINALIZED_UPGRADE, bytesLeftToMove, -1);
       }