HDFS-6959 Make the HDFS home directory location customizable. Contributed by Yongjun Zhang

(cherry picked from commit f4caedfcbf)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -176,6 +176,9 @@ Release 2.6.0 - UNRELEASED
     HDFS-4257. The ReplaceDatanodeOnFailure policies could have a forgiving
     option (szetszwo via cmccabe)
 
+    HDFS-6959. Make the HDFS home directory location customizable. (yzhang via
+    cmccabe)
+
   OPTIMIZATIONS
 
     HDFS-6690. Deduplicate xattr names in memory. (wang)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -41,6 +41,8 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final int     DFS_STREAM_BUFFER_SIZE_DEFAULT = 4096;
   public static final String  DFS_BYTES_PER_CHECKSUM_KEY = "dfs.bytes-per-checksum";
   public static final int     DFS_BYTES_PER_CHECKSUM_DEFAULT = 512;
+  public static final String  DFS_USER_HOME_DIR_PREFIX_KEY = "dfs.user.home.dir.prefix";
+  public static final String  DFS_USER_HOME_DIR_PREFIX_DEFAULT = "/user";
   public static final String  DFS_CLIENT_RETRY_POLICY_ENABLED_KEY = "dfs.client.retry.policy.enabled";
   public static final boolean DFS_CLIENT_RETRY_POLICY_ENABLED_DEFAULT = false; 
   public static final String  DFS_CLIENT_RETRY_POLICY_SPEC_KEY = "dfs.client.retry.policy.spec";

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -102,6 +102,8 @@ import com.google.common.base.Preconditions;
 public class DistributedFileSystem extends FileSystem {
   private Path workingDir;
   private URI uri;
+  private String homeDirPrefix =
+      DFSConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT;
 
   DFSClient dfs;
   private boolean verifyChecksum = true;
@@ -136,7 +138,10 @@ public class DistributedFileSystem extends FileSystem {
     if (host == null) {
       throw new IOException("Incomplete HDFS URI, no host: "+ uri);
     }
-
+    homeDirPrefix = conf.get(
+        DFSConfigKeys.DFS_USER_HOME_DIR_PREFIX_KEY,
+        DFSConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT);
+    
     this.dfs = new DFSClient(uri, conf, statistics);
     this.uri = URI.create(uri.getScheme()+"://"+uri.getAuthority());
     this.workingDir = getHomeDirectory();
@@ -167,10 +172,10 @@ public class DistributedFileSystem extends FileSystem {
     workingDir = fixRelativePart(dir);
   }
 
-  
   @Override
   public Path getHomeDirectory() {
-    return makeQualified(new Path("/user/" + dfs.ugi.getShortUserName()));
+    return makeQualified(new Path(homeDirPrefix + "/"
+        + dfs.ugi.getShortUserName()));
   }
 
   /**

hadoop-hdfs-project/hadoop-hdfs/src/main/resources/hdfs-default.xml

@@ -2090,4 +2090,12 @@
   </description>
 </property>
 
+<property>
+  <name>dfs.user.home.dir.prefix</name>
+  <value>/user</value>
+  <description>The directory to prepend to user name to get the user's
+    home direcotry.
+  </description>
+</property>
+
 </configuration>

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestLocalDFS.java

@@ -90,7 +90,9 @@ public class TestLocalDFS {
 
       // test home directory
       Path home = 
-        fileSys.makeQualified(new Path("/user/" + getUserName(fileSys))); 
+        fileSys.makeQualified(
+            new Path(DFSConfigKeys.DFS_USER_HOME_DIR_PREFIX_DEFAULT
+                + "/" + getUserName(fileSys))); 
       Path fsHome = fileSys.getHomeDirectory();
       assertEquals(home, fsHome);
 
@@ -99,4 +101,29 @@ public class TestLocalDFS {
       cluster.shutdown();
     }
   }
+  
+  /**
+   * Tests get/set working directory in DFS.
+   */
+  @Test(timeout=30000)
+  public void testHomeDirectory() throws IOException {
+    final String[] homeBases = new String[] {"/home", "/home/user"};
+    Configuration conf = new HdfsConfiguration();
+    for (final String homeBase : homeBases) {
+      conf.set(DFSConfigKeys.DFS_USER_HOME_DIR_PREFIX_KEY, homeBase);
+      MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf).build();
+      FileSystem fileSys = cluster.getFileSystem();
+      try {    
+        // test home directory
+        Path home = 
+            fileSys.makeQualified(
+                new Path(homeBase + "/" + getUserName(fileSys))); 
+        Path fsHome = fileSys.getHomeDirectory();
+        assertEquals(home, fsHome);
+      } finally {
+        fileSys.close();
+        cluster.shutdown();
+      }
+    }
+  }
 }