From 7ff326129dc3413e5e978feadd66e4eae3506e8d Mon Sep 17 00:00:00 2001
From: Daniel-009497 <18710890153@163.com>
Date: Wed, 21 Dec 2022 07:12:02 +0800
Subject: [PATCH] HDFS-16871 DiskBalancer process may throw
 IllegalArgumentException when the target DataNode has capital letter in
 hostname (#5240)

---
 .../hdfs/server/diskbalancer/datamodel/DiskBalancerCluster.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/diskbalancer/datamodel/DiskBalancerCluster.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/diskbalancer/datamodel/DiskBalancerCluster.java
index c801f36ea52..7e935a3f820 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/diskbalancer/datamodel/DiskBalancerCluster.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/diskbalancer/datamodel/DiskBalancerCluster.java
@@ -389,6 +389,6 @@ public class DiskBalancerCluster {
    * @return DiskBalancerDataNode.
    */
   public DiskBalancerDataNode getNodeByName(String hostName) {
-    return hostNames.get(hostName);
+    return hostNames.get(hostName.toLowerCase(Locale.US));
   }
 }