From 0be0f1ce1da984ff3a8fd4b079297ead2dc6722d Mon Sep 17 00:00:00 2001
From: Xiaoyu Yao <xyao@apache.org>
Date: Wed, 14 Mar 2018 10:38:00 -0700
Subject: [PATCH] HDFS-13275. Adding log for BlockPoolManager#refreshNamenodes
 failures. Contributed by Ajay Kumar.

---
 .../server/datanode/BlockPoolManager.java     | 24 ++++++++++++++-----
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolManager.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolManager.java
index 141550ef3b4..b03c51120ac 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolManager.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/BlockPoolManager.java
@@ -146,13 +146,25 @@ void joinAll() {
   
   void refreshNamenodes(Configuration conf)
       throws IOException {
-    LOG.info("Refresh request received for nameservices: " + conf.get
-            (DFSConfigKeys.DFS_NAMESERVICES));
+    LOG.info("Refresh request received for nameservices: " +
+        conf.get(DFSConfigKeys.DFS_NAMESERVICES));
 
-    Map<String, Map<String, InetSocketAddress>> newAddressMap = DFSUtil
-            .getNNServiceRpcAddressesForCluster(conf);
-    Map<String, Map<String, InetSocketAddress>> newLifelineAddressMap = DFSUtil
-            .getNNLifelineRpcAddressesForCluster(conf);
+    Map<String, Map<String, InetSocketAddress>> newAddressMap = null;
+    Map<String, Map<String, InetSocketAddress>> newLifelineAddressMap = null;
+
+    try {
+      newAddressMap =
+          DFSUtil.getNNServiceRpcAddressesForCluster(conf);
+      newLifelineAddressMap =
+          DFSUtil.getNNLifelineRpcAddressesForCluster(conf);
+    } catch (IOException ioe) {
+      LOG.warn("Unable to get NameNode addresses.");
+    }
+
+    if (newAddressMap == null || newAddressMap.isEmpty()) {
+      throw new IOException("No services to connect, missing NameNode " +
+          "address.");
+    }
 
     synchronized (refreshNamenodesLock) {
       doRefreshNamenodes(newAddressMap, newLifelineAddressMap);