diff --git a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
index 840123e40a..48b6b16d83 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
+++ b/hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
@@ -733,6 +733,9 @@ Release 2.5.0 - UNRELEASED
     HDFS-6601. Issues in finalizing rolling upgrade when there is a layout 
     version change (kihwal)
 
+    HDFS-6418. Regression: DFS_NAMENODE_USER_NAME_KEY missing
+    (szetszwo via stevel)
+
   BREAKDOWN OF HDFS-2006 SUBTASKS AND RELATED JIRAS
 
     HDFS-6299. Protobuf for XAttr and client-side implementation. (Yi Liu via umamahesh)
diff --git a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
index edadbd5d21..2d825effb8 100644
--- a/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
+++ b/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java
@@ -496,16 +496,26 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final String  DFS_NAMENODE_STARTUP_KEY = "dfs.namenode.startup";
   public static final String  DFS_DATANODE_KEYTAB_FILE_KEY = "dfs.datanode.keytab.file";
   public static final String  DFS_DATANODE_KERBEROS_PRINCIPAL_KEY = "dfs.datanode.kerberos.principal";
+  @Deprecated
+  public static final String  DFS_DATANODE_USER_NAME_KEY = DFS_DATANODE_KERBEROS_PRINCIPAL_KEY;
   public static final String  DFS_DATANODE_SHARED_FILE_DESCRIPTOR_PATHS = "dfs.datanode.shared.file.descriptor.paths";
   public static final String  DFS_DATANODE_SHARED_FILE_DESCRIPTOR_PATHS_DEFAULT = "/dev/shm,/tmp";
   public static final String  DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS = "dfs.short.circuit.shared.memory.watcher.interrupt.check.ms";
   public static final int     DFS_SHORT_CIRCUIT_SHARED_MEMORY_WATCHER_INTERRUPT_CHECK_MS_DEFAULT = 60000;
   public static final String  DFS_NAMENODE_KEYTAB_FILE_KEY = "dfs.namenode.keytab.file";
   public static final String  DFS_NAMENODE_KERBEROS_PRINCIPAL_KEY = "dfs.namenode.kerberos.principal";
+  @Deprecated
+  public static final String  DFS_NAMENODE_USER_NAME_KEY = DFS_NAMENODE_KERBEROS_PRINCIPAL_KEY;
   public static final String  DFS_NAMENODE_KERBEROS_INTERNAL_SPNEGO_PRINCIPAL_KEY = "dfs.namenode.kerberos.internal.spnego.principal";
+  @Deprecated
+  public static final String  DFS_NAMENODE_INTERNAL_SPNEGO_USER_NAME_KEY = DFS_NAMENODE_KERBEROS_INTERNAL_SPNEGO_PRINCIPAL_KEY;
   public static final String  DFS_SECONDARY_NAMENODE_KEYTAB_FILE_KEY = "dfs.secondary.namenode.keytab.file";
   public static final String  DFS_SECONDARY_NAMENODE_KERBEROS_PRINCIPAL_KEY = "dfs.secondary.namenode.kerberos.principal";
+  @Deprecated
+  public static final String  DFS_SECONDARY_NAMENODE_USER_NAME_KEY = DFS_SECONDARY_NAMENODE_KERBEROS_PRINCIPAL_KEY;
   public static final String  DFS_SECONDARY_NAMENODE_KERBEROS_INTERNAL_SPNEGO_PRINCIPAL_KEY = "dfs.secondary.namenode.kerberos.internal.spnego.principal";
+  @Deprecated
+  public static final String  DFS_SECONDARY_NAMENODE_INTERNAL_SPNEGO_USER_NAME_KEY = DFS_SECONDARY_NAMENODE_KERBEROS_INTERNAL_SPNEGO_PRINCIPAL_KEY;
   public static final String  DFS_NAMENODE_NAME_CACHE_THRESHOLD_KEY = "dfs.namenode.name.cache.threshold";
   public static final int     DFS_NAMENODE_NAME_CACHE_THRESHOLD_DEFAULT = 10;
   public static final String  DFS_NAMENODE_LEGACY_OIV_IMAGE_DIR_KEY = "dfs.namenode.legacy-oiv-image.dir";