HDFS-4963. Improve multihoming support in namenode. Contributed by Arpit Agarwal.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-1@1510855 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -31,6 +31,9 @@ Release 1.3.0 - unreleased
 
     MAPREDUCE-5408. Backport MAPREDUCE-336 to branch-1. (acmurthy)
 
+    HDFS-4963. Improve multihoming support in namenode. (Arpit Agarwal via
+    cnauroth)
+
   BUG FIXES
 
     MAPREDUCE-5047. keep.failed.task.files=true causes job failure on 

src/core/org/apache/hadoop/util/StringUtils.java

@@ -539,7 +539,20 @@ public class StringUtils {
    */
   public static void startupShutdownMessage(Class<?> clazz, String[] args,
                                      final org.apache.commons.logging.Log LOG) {
-    final String hostname = getHostname();
+    startupShutdownMessage(clazz, getHostname(), args, LOG);
+  }
+
+  /**
+   * Print a log message for starting up and shutting down
+   * @param clazz the class of the server
+   * @param hostname the hostname that the server is listening on.
+   * @param args arguments
+   * @param LOG the target log object
+   */
+  public static void startupShutdownMessage(Class<?> clazz,
+                                            final String hostname,
+                                            String[] args,
+                                            final org.apache.commons.logging.Log LOG) {
     final String classname = clazz.getSimpleName();
     LOG.info(
         toStartupShutdownString("STARTUP_MSG: ", new String[] {

src/hdfs/hdfs-default.xml

@@ -438,6 +438,15 @@ creations/deletions), or "all".</description>
   </description>
 </property>
 
+<property>
+  <name>dfs.namenode.master.name</name>
+  <description>
+    The hostname that the NameNode will bind to. This setting should be used
+    when the NameNode is multihomed to force the NameNode to bind to a
+    specific hostname or IP address.
+  </description>
+</property>
+
 <property>
   <name>dfs.namenode.delegation.key.update-interval</name>
   <value>86400000</value>

src/hdfs/org/apache/hadoop/hdfs/DFSConfigKeys.java

@@ -122,6 +122,7 @@ public class DFSConfigKeys extends CommonConfigurationKeys {
   public static final boolean DFS_DATANODE_USE_DN_HOSTNAME_DEFAULT = false;
   public static final String  DFS_DATANODE_SYNCONCLOSE_KEY = "dfs.datanode.synconclose";
   public static final boolean DFS_DATANODE_SYNCONCLOSE_DEFAULT = false;
+  public static final String  DFS_NAMENODE_MASTER_NAME = "dfs.namenode.master.name";
 
   //Delegation token related keys
   public static final String  DFS_NAMENODE_DELEGATION_KEY_UPDATE_INTERVAL_KEY = "dfs.namenode.delegation.key.update-interval";

src/hdfs/org/apache/hadoop/hdfs/DFSUtil.java

@@ -116,7 +116,24 @@ public class DFSUtil {
     return blkLocations;
   }
 
-  /** Create a URI from the scheme and address */
+  /** Create a URI from the scheme, host and port */
+  public static URI createUri(String scheme,
+                              String hostName,
+                              int port) {
+    try {
+      return new URI(scheme, null, hostName, port, null, null, null);
+    } catch (URISyntaxException ue) {
+      throw new IllegalArgumentException(ue);
+    }
+  }
+
+  /** Create a URI from the scheme and address.
+   *
+   * Marked as deprecated because querying the hostname from the socket
+   * address does not work reliably when dealing with multi-homed hosts.
+   * Prefer using the hostname explicitly instead (when available).
+   */
+  @Deprecated
   public static URI createUri(String scheme, InetSocketAddress address) {
     try {
       return new URI(scheme, null, address.getHostName(), address.getPort(),

src/hdfs/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -79,7 +79,7 @@ public class DistributedFileSystem extends FileSystem {
   /** @deprecated */
   public DistributedFileSystem(InetSocketAddress namenode,
     Configuration conf) throws IOException {
-    initialize(NameNode.getUri(namenode), conf);
+    initialize(NameNode.getUri(conf, namenode), conf);
   }
 
   /** @deprecated */

src/hdfs/org/apache/hadoop/hdfs/HftpFileSystem.java

@@ -48,6 +48,7 @@ import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifie
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenRenewer;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSelector;
 import org.apache.hadoop.hdfs.server.namenode.JspHelper;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.StreamFile;
 import org.apache.hadoop.hdfs.tools.DelegationTokenFetcher;
 import org.apache.hadoop.io.Text;
@@ -84,6 +85,7 @@ public class HftpFileSystem extends FileSystem
   }
 
   public static final Text TOKEN_KIND = new Text("HFTP delegation");
+  private String masterHostName = null;
   
   protected UserGroupInformation ugi; 
   private boolean remoteIsInsecure = false;
@@ -136,7 +138,17 @@ public class HftpFileSystem extends FileSystem
     super.initialize(name, conf);
     this.ugi = UserGroupInformation.getCurrentUser();
     this.nnAddr = getNamenodeAddr(name);
-    this.hftpURI = DFSUtil.createUri(name.getScheme(), nnAddr);
+    this.masterHostName = conf.get(DFSConfigKeys.DFS_NAMENODE_MASTER_NAME);
+    this.hftpURI = DFSUtil.createUri(
+        name.getScheme(), getMasterHostName(), nnAddr.getPort());
+  }
+
+  String getMasterHostName() {
+    if (masterHostName == null || masterHostName.isEmpty()) {
+      return nnAddr.getHostName();
+    } else {
+      return masterHostName;
+    }
   }
   
   protected void initDelegationToken() throws IOException {
@@ -281,7 +293,7 @@ public class HftpFileSystem extends FileSystem
     try {
       query = updateQuery(query);
       final URL url = new URI(getUnderlyingProtocol(), null, 
-			      nnAddr.getHostName(),
+			      getMasterHostName(),
 			      nnAddr.getPort(), path, query, null).toURL();
       if (LOG.isTraceEnabled()) {
         LOG.trace("url=" + url);
@@ -680,6 +692,7 @@ public class HftpFileSystem extends FileSystem
       InetSocketAddress serviceAddr = SecurityUtil.getTokenServiceAddr(token);
       return DelegationTokenFetcher.
         renewDelegationToken(getUnderlyingProtocol(),
+                             NameNode.getNamenodeHostName(conf, serviceAddr),
                              serviceAddr,
                              (Token<DelegationTokenIdentifier>) token,
                              conf);
@@ -694,6 +707,7 @@ public class HftpFileSystem extends FileSystem
       InetSocketAddress serviceAddr = SecurityUtil.getTokenServiceAddr(token);
       DelegationTokenFetcher.
         cancelDelegationToken(getUnderlyingProtocol(),
+                              NameNode.getNamenodeHostName(conf, serviceAddr),
                               serviceAddr,
                               (Token<DelegationTokenIdentifier>) token,
                               conf);

src/hdfs/org/apache/hadoop/hdfs/security/token/delegation/DelegationTokenSelector.java

@@ -52,11 +52,12 @@ public class DelegationTokenSelector
     
     int nnRpcPort = NameNode.DEFAULT_PORT;
     if (nnServiceName != null) {
-      nnRpcPort = NetUtils.createSocketAddr(nnServiceName, nnRpcPort).getPort(); 
+      nnRpcPort = NetUtils.createSocketAddr(nnServiceName, nnRpcPort).getPort();
     }
-    
+
+    final String nameNodeHostName = NameNode.getNamenodeHostName(conf, nnAddr);
     final Text serviceName = SecurityUtil.buildTokenService(
-        NetUtils.makeSocketAddr(nnAddr.getHostName(), nnRpcPort));
+        NetUtils.makeSocketAddr(nameNodeHostName, nnRpcPort));
     return INSTANCE.selectToken(serviceName, ugi.getTokens());
   }
 

src/hdfs/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -467,9 +467,7 @@ public class FSNamesystem implements FSConstants, FSNamesystemMBean, FSClusterSt
       dnsToSwitchMapping.resolve(new ArrayList<String>(hostsReader.getHosts()));
     }
     
-    InetSocketAddress socAddr = NameNode.getAddress(conf);
-    this.nameNodeHostName = socAddr.getHostName();
-    
+    this.nameNodeHostName = NameNode.getNamenodeHostName(conf);
     registerWith(DefaultMetricsSystem.INSTANCE);
   }
 

src/hdfs/org/apache/hadoop/hdfs/server/namenode/NameNode.java

@@ -22,6 +22,7 @@ import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_DELEGATION_TOKEN
 
 import java.io.File;
 import java.io.IOException;
+import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.URI;
 import java.security.PrivilegedExceptionAction;
@@ -218,7 +219,7 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
    */
   public static void setServiceAddress(Configuration conf,
                                            String address) {
-    LOG.info("Setting ADDRESS " + address);
+    LOG.info("Setting RPC Service address: " + address);
     conf.set(DFSConfigKeys.DFS_NAMENODE_SERVICE_RPC_ADDRESS_KEY, address);
   }
   
@@ -238,18 +239,50 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
     return getAddress(addr);
   }
 
-  public static InetSocketAddress getAddress(Configuration conf) {
+  private static String getAddressString(Configuration conf) {
     String addr = conf.get(DFSConfigKeys.DFS_NAMENODE_RPC_ADDRESS_KEY);
     if (addr == null || addr.isEmpty()) {
-      return getAddress(FileSystem.getDefaultUri(conf).toString());
+      addr = FileSystem.getDefaultUri(conf).toString();
     }
-    return getAddress(addr);
+    return addr;
+  }
+
+  public static InetSocketAddress getAddress(Configuration conf) {
+    return getAddress(getAddressString(conf));
   }
 
-  public static URI getUri(InetSocketAddress namenode) {
+  /**
+   * If DFS_NAMENODE_MASTER_NAME is set then use that else query the
+   * hostname from the socket address. The latter behavior is legacy but
+   * wrong since it can behave unexpectedly when the namenode is multi-
+   * homed.
+   *
+   * @param conf configuration database
+   * @param address socket address for the local endpoint.
+   * @return The hostname to connect to the namenode.
+   */
+  public static String getNamenodeHostName(Configuration conf,
+      InetSocketAddress address) {
+    String masterHostName =
+        conf.get(DFSConfigKeys.DFS_NAMENODE_MASTER_NAME);
+
+    if (masterHostName == null || masterHostName.isEmpty()) {
+      return address.getHostName();
+    } else {
+      return masterHostName;
+    }
+  }
+
+  public static String getNamenodeHostName(Configuration conf) {
+    return getNamenodeHostName(conf, getAddress(conf));
+  }
+
+  public static URI getUri(Configuration conf,
+      InetSocketAddress namenode) {
     int port = namenode.getPort();
-    String portString = port == DEFAULT_PORT ? "" : (":"+port);
-    return URI.create("hdfs://"+ namenode.getHostName()+portString);
+    String portString = port == DEFAULT_PORT ? "" : (":" + port);
+    String hostname = getNamenodeHostName(conf, namenode);
+    return URI.create("hdfs://"+ hostname + portString);
   }
 
   /**
@@ -266,8 +299,8 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
    * Modifies the configuration passed to contain the service rpc address setting
    */
   protected void setRpcServiceServerAddress(Configuration conf) {
-    String address = serviceRPCAddress.getHostName() + ":"
-        + serviceRPCAddress.getPort();
+    String hostname = getNamenodeHostName(conf, serviceRPCAddress);
+    String address = hostname + ":" + serviceRPCAddress.getPort();
     setServiceAddress(conf, address);
   }
 
@@ -279,8 +312,10 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
   private void initialize(Configuration conf) throws IOException {
     InetSocketAddress socAddr = NameNode.getAddress(conf);
     UserGroupInformation.setConfiguration(conf);
-    SecurityUtil.login(conf, DFSConfigKeys.DFS_NAMENODE_KEYTAB_FILE_KEY, 
-        DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY, socAddr.getHostName());
+    SecurityUtil.login(conf,
+        DFSConfigKeys.DFS_NAMENODE_KEYTAB_FILE_KEY,
+        DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY,
+        getNamenodeHostName(conf, socAddr));
     int handlerCount = conf.getInt("dfs.namenode.handler.count", 10);
     
     // set service-level authorization security policy
@@ -313,26 +348,29 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
     InetSocketAddress dnSocketAddr = getServiceRpcServerAddress(conf);
     if (dnSocketAddr != null) {
       int serviceHandlerCount =
-        conf.getInt(DFSConfigKeys.DFS_NAMENODE_SERVICE_HANDLER_COUNT_KEY,
-                    DFSConfigKeys.DFS_NAMENODE_SERVICE_HANDLER_COUNT_DEFAULT);
-      this.serviceRpcServer = RPC.getServer(this, dnSocketAddr.getHostName(), 
-          dnSocketAddr.getPort(), serviceHandlerCount,
-          false, conf, namesystem.getDelegationTokenSecretManager());
+          conf.getInt(DFSConfigKeys.DFS_NAMENODE_SERVICE_HANDLER_COUNT_KEY,
+              DFSConfigKeys.DFS_NAMENODE_SERVICE_HANDLER_COUNT_DEFAULT);
+      this.serviceRpcServer = RPC.getServer(this,
+          getNamenodeHostName(conf, dnSocketAddr), dnSocketAddr.getPort(),
+          serviceHandlerCount, false, conf,
+          namesystem.getDelegationTokenSecretManager());
       this.serviceRPCAddress = this.serviceRpcServer.getListenerAddress();
       setRpcServiceServerAddress(conf);
     }
-    this.server = RPC.getServer(this, socAddr.getHostName(),
+    this.server = RPC.getServer(this, getNamenodeHostName(conf, socAddr),
         socAddr.getPort(), handlerCount, false, conf, namesystem
         .getDelegationTokenSecretManager());
     // Set terse exception whose stack trace won't be logged
     this.server.addTerseExceptions(SafeModeException.class);
-    
+
     // The rpc-server port can be ephemeral... ensure we have the correct info
-    this.serverAddress = this.server.getListenerAddress(); 
-    FileSystem.setDefaultUri(conf, getUri(serverAddress));
-    LOG.info("Namenode up at: " + this.serverAddress);
+    // The ephemeral port is primarily used when testing.
+    this.serverAddress = this.server.getListenerAddress();
+    URI serverUri = getUri(conf, serverAddress);
+    FileSystem.setDefaultUri(conf, serverUri);
+    LOG.info("Namenode up at: " + serverUri);
+
 
-    
 
     startHttpServer(conf);
     this.server.start();  //start RPC server   
@@ -380,14 +418,14 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
     final InetSocketAddress infoSocAddr = NetUtils.createSocketAddr(infoAddr);
     
     if (SecurityUtil.useKsslAuth()) {
-      String httpsUser = SecurityUtil.getServerPrincipal(conf
-          .get(DFSConfigKeys.DFS_NAMENODE_KRB_HTTPS_USER_NAME_KEY), infoSocAddr
-          .getHostName());
+      String httpsUser = SecurityUtil.getServerPrincipal(
+          conf.get(DFSConfigKeys.DFS_NAMENODE_KRB_HTTPS_USER_NAME_KEY),
+          getNamenodeHostName(conf, infoSocAddr));
       // Kerberized SSL servers must be run from the host principal...
       LOG.info("Logging in as " + httpsUser + " to start http server.");
       SecurityUtil.login(conf, DFSConfigKeys.DFS_NAMENODE_KEYTAB_FILE_KEY,
-          DFSConfigKeys.DFS_NAMENODE_KRB_HTTPS_USER_NAME_KEY, infoSocAddr
-              .getHostName());
+          DFSConfigKeys.DFS_NAMENODE_KRB_HTTPS_USER_NAME_KEY,
+              getNamenodeHostName(conf, infoSocAddr));
     }
 
     UserGroupInformation ugi = UserGroupInformation.getLoginUser();
@@ -395,7 +433,7 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
       this.httpServer = ugi.doAs(new PrivilegedExceptionAction<HttpServer>() {
         @Override
         public HttpServer run() throws IOException, InterruptedException {
-          String infoHost = infoSocAddr.getHostName();
+          String infoHost = getNamenodeHostName(conf, infoSocAddr);
           int infoPort = infoSocAddr.getPort();
           httpServer = new HttpServer("hdfs", infoHost, infoPort, 
               infoPort == 0, conf, 
@@ -409,8 +447,9 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
                     DFSConfigKeys.DFS_NAMENODE_INTERNAL_SPENGO_USER_NAME_KEY);
                 if (principalInConf != null && !principalInConf.isEmpty()) {
                   params.put("kerberos.principal",
-                      SecurityUtil.getServerPrincipal(principalInConf,
-                          serverAddress.getHostName()));
+                      SecurityUtil.getServerPrincipal(
+                          principalInConf,
+                          getNamenodeHostName(conf, serverAddress)));
                 }
                 String httpKeytab = conf.get(
                   DFSConfigKeys.DFS_WEB_AUTHENTICATION_KERBEROS_KEYTAB_KEY);
@@ -455,7 +494,7 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
                     .put(
                         DFSConfigKeys.DFS_WEB_AUTHENTICATION_KERBEROS_PRINCIPAL_KEY,
                         SecurityUtil.getServerPrincipal(principalInConf,
-                            serverAddress.getHostName()));
+                            getNamenodeHostName(conf, serverAddress)));
               }
               String httpKeytab = conf
                   .get(DFSConfigKeys.DFS_WEB_AUTHENTICATION_KERBEROS_KEYTAB_KEY);
@@ -529,13 +568,15 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
     } finally {
       if (SecurityUtil.useKsslAuth()) {
         // Go back to being the correct Namenode principal
-        LOG.info("Logging back in as "
-            + SecurityUtil.getServerPrincipal(conf
-                .get(DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY), serverAddress
-                .getHostName()) + " following http server start.");
-        SecurityUtil.login(conf, DFSConfigKeys.DFS_NAMENODE_KEYTAB_FILE_KEY,
-            DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY, serverAddress
-                .getHostName());
+        LOG.info("Logging back in as " +
+            SecurityUtil.getServerPrincipal(
+                conf.get(DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY),
+                getNamenodeHostName(conf, serverAddress)) +
+            " following http server start.");
+        SecurityUtil.login(
+            conf, DFSConfigKeys.DFS_NAMENODE_KEYTAB_FILE_KEY,
+            DFSConfigKeys.DFS_NAMENODE_USER_NAME_KEY,
+            getNamenodeHostName(conf, serverAddress));
       }
     }
   }
@@ -921,7 +962,7 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
 
   @Override
   public DirectoryListing getListing(String src, byte[] startAfter)
-  throws IOException {
+      throws IOException {
     DirectoryListing files = namesystem.getListing(src, startAfter);
     myMetrics.incrNumGetListingOps();
     if (files != null) {
@@ -1480,11 +1521,33 @@ public class NameNode implements ClientProtocol, DatanodeProtocol,
     return namenode;
   }
     
+  /**
+   * Get the hostname that the namenode is listening on.
+   *
+   * @return
+   */
+  private static String getHostname(Configuration conf) throws Exception {
+    if (conf == null) {
+      conf = new Configuration();
+    }
+
+    String masterHostName =
+        conf.get(DFSConfigKeys.DFS_NAMENODE_MASTER_NAME);
+
+    if (masterHostName == null || masterHostName.isEmpty()) {
+      return InetAddress.getLocalHost().toString();
+    } else {
+      InetAddress address = InetAddress.getByName(masterHostName);
+      return address.toString();
+    }
+  }
+
   /**
    */
   public static void main(String argv[]) throws Exception {
     try {
-      StringUtils.startupShutdownMessage(NameNode.class, argv, LOG);
+      StringUtils.startupShutdownMessage(
+          NameNode.class, getHostname(null), argv, LOG);
       NameNode namenode = createNameNode(argv, null);
       if (namenode != null)
         namenode.join();

src/hdfs/org/apache/hadoop/hdfs/tools/DelegationTokenFetcher.java

@@ -200,7 +200,32 @@ public class DelegationTokenFetcher {
                                             String renewer,
                                             Configuration conf
                                             ) throws IOException {
-    final String renewAddress = getRenewAddress(protocol, nnAddr, conf);
+    return getDTfromRemote(
+        protocol,
+        nnAddr.getHostName(),
+        nnAddr,
+        renewer,
+        conf);
+  }
+
+  /**
+   * Utility method to obtain a delegation token over http
+   * @param protocol whether to use http or https
+   * @param hostname the NameNode's hostname. This may be different from the
+   *                 hostname looked up via in the address if the namenode is
+   *                 multihomed.
+   * @param nnAddr the address for the NameNode
+   * @param renewer User that is renewing the ticket in such a request
+   * @param conf the configuration
+   */
+  static public Credentials getDTfromRemote(String protocol,
+                                            String hostname,
+                                            final InetSocketAddress nnAddr,
+                                            String renewer,
+                                            Configuration conf
+                                            ) throws IOException {
+    final String renewAddress =
+        getRenewAddress(protocol, hostname, nnAddr, conf);
     final boolean https = "https".equals(protocol);
 
     try {
@@ -252,6 +277,7 @@ public class DelegationTokenFetcher {
    * https and the NN's https port.
    */
   protected static String getRenewAddress(String protocol,
+                                          String hostname,
                                           InetSocketAddress addr,
                                           Configuration conf) {
     if (SecurityUtil.useKsslAuth() && "http".equals(protocol)) {
@@ -261,12 +287,15 @@ public class DelegationTokenFetcher {
                     DFSConfigKeys.DFS_NAMENODE_HTTPS_PORT_DEFAULT);
       addr = new InetSocketAddress(addr.getAddress(), port);
     }
-    return DFSUtil.createUri(protocol, addr).toString();
+    return DFSUtil.createUri(protocol, hostname, addr.getPort()).toString();
   }
 
   /**
    * Renew a Delegation Token.
    * @param protocol The protocol to renew over (http or https)
+   * @param hostname the NameNode's hostname. This may be different from the
+   *                 hostname looked up via in the address if the namenode is
+   *                 multihomed.
    * @param addr the address of the NameNode
    * @param tok the token to renew
    * @param conf the configuration
@@ -274,11 +303,13 @@ public class DelegationTokenFetcher {
    * @throws IOException
    */
   static public long renewDelegationToken(String protocol,
+                                          String hostname,
                                           InetSocketAddress addr,
                                           Token<DelegationTokenIdentifier> tok,
                                           Configuration conf
                                           ) throws IOException {
-    final String renewAddress = getRenewAddress(protocol, addr, conf);
+    final String renewAddress =
+        getRenewAddress(protocol, hostname, addr, conf);
     final StringBuilder buf = new StringBuilder(renewAddress);
     final String service = tok.getService().toString();
     buf.append(RenewDelegationTokenServlet.PATH_SPEC);
@@ -353,16 +384,20 @@ public class DelegationTokenFetcher {
   
   /**
    * Cancel a Delegation Token.
-   * @param nnAddr the NameNode's address
+   * @param hostname the NameNode's hostname. This may be different from the
+   *                 hostname looked up via in the address if the namenode is
+   *                 multihomed.
+   * @param addr the NameNode's address
    * @param tok the token to cancel
    * @throws IOException
    */
   static public void cancelDelegationToken(String protocol,
+                                           String hostname,
                                            InetSocketAddress addr,
                                            Token<DelegationTokenIdentifier> tok,
                                            Configuration conf
                                            ) throws IOException {
-    final String renewAddress = getRenewAddress(protocol, addr, conf);
+    final String renewAddress = getRenewAddress(protocol, hostname, addr, conf);
     StringBuilder buf = new StringBuilder(renewAddress);
     buf.append(CancelDelegationTokenServlet.PATH_SPEC);
     buf.append("?");

src/hdfs/org/apache/hadoop/hdfs/web/WebHdfsFileSystem.java

@@ -57,6 +57,7 @@ import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenIdentifie
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenRenewer;
 import org.apache.hadoop.hdfs.security.token.delegation.DelegationTokenSelector;
 import org.apache.hadoop.hdfs.server.namenode.JspHelper;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.SafeModeException;
 import org.apache.hadoop.hdfs.web.resources.AccessTimeParam;
 import org.apache.hadoop.hdfs.web.resources.BlockSizeParam;
@@ -144,6 +145,7 @@ public class WebHdfsFileSystem extends FileSystem
   private final AuthenticatedURL.Token authToken = new AuthenticatedURL.Token();
   private RetryPolicy retryPolicy = null;
   private Path workingDir;
+  private String masterHostName = null;
 
   {
     try {
@@ -172,11 +174,21 @@ public class WebHdfsFileSystem extends FileSystem
             );
     this.workingDir = getHomeDirectory();
 
+    masterHostName = conf.get(DFSConfigKeys.DFS_NAMENODE_MASTER_NAME);
+
     if (UserGroupInformation.isSecurityEnabled()) {
       initDelegationToken();
     }
   }
 
+  String getMasterHostName() {
+    if (masterHostName == null || masterHostName.isEmpty()) {
+      return nnAddr.getHostName();
+    } else {
+      return masterHostName;
+    }
+  }
+
   protected void initDelegationToken() throws IOException {
     // look for webhdfs token, then try hdfs
     final Text serviceName = SecurityUtil.buildTokenService(nnAddr);
@@ -214,7 +226,7 @@ public class WebHdfsFileSystem extends FileSystem
   @Override
   public URI getUri() {
     try {
-      return new URI(SCHEME, null, nnAddr.getHostName(), nnAddr.getPort(),
+      return new URI(SCHEME, null, getMasterHostName(), nnAddr.getPort(),
           null, null, null);
     } catch (URISyntaxException e) {
       return null;
@@ -337,7 +349,7 @@ public class WebHdfsFileSystem extends FileSystem
    * @throws IOException on error constructing the URL
    */
   private URL getNamenodeURL(String path, String query) throws IOException {
-    final URL url = new URL("http", nnAddr.getHostName(),
+    final URL url = new URL("http", getMasterHostName(),
           nnAddr.getPort(), path + '?' + query);
     if (LOG.isTraceEnabled()) {
       LOG.trace("url=" + url);
@@ -903,7 +915,10 @@ public class WebHdfsFileSystem extends FileSystem
         final Token<?> token, final Configuration conf) throws IOException {
       
       final InetSocketAddress nnAddr = SecurityUtil.getTokenServiceAddr(token);
-      final URI uri = DFSUtil.createUri(WebHdfsFileSystem.SCHEME, nnAddr);
+      final URI uri = DFSUtil.createUri(
+          WebHdfsFileSystem.SCHEME,
+          NameNode.getNamenodeHostName(conf, nnAddr),
+          nnAddr.getPort());
       return (WebHdfsFileSystem)FileSystem.get(uri, conf);
     }
 

src/test/org/apache/hadoop/hdfs/MiniDFSCluster.java

@@ -347,7 +347,8 @@ public class MiniDFSCluster {
       InetSocketAddress nnAddr = nameNode.getNameNodeAddress(); 
       int nameNodePort = nnAddr.getPort(); 
       FileSystem.setDefaultUri(conf, 
-                               "hdfs://"+ nnAddr.getHostName() +
+                               "hdfs://" +
+                               nameNode.getNamenodeHostName(conf, nnAddr) +
                                ":" + Integer.toString(nameNodePort));
     }
     

src/test/org/apache/hadoop/hdfs/MiniDFSClusterWithNodeGroup.java

@@ -83,7 +83,8 @@ public class MiniDFSClusterWithNodeGroup extends MiniDFSCluster {
         InetSocketAddress nnAddr = nameNode.getNameNodeAddress(); 
         int nameNodePort = nnAddr.getPort(); 
         FileSystem.setDefaultUri(conf, 
-                                 "hdfs://"+ nnAddr.getHostName() +
+                                 "hdfs://" +
+                                 nameNode.getNamenodeHostName(conf, nnAddr) +
                                  ":" + Integer.toString(nameNodePort));
       }
     if (racks != null && numDataNodes > racks.length ) {

src/test/org/apache/hadoop/hdfs/TestDefaultNameNodePort.java

@@ -59,9 +59,10 @@ public class TestDefaultNameNodePort {
   }
 
   public void testGetUri() {
-    assertEquals(NameNode.getUri(new InetSocketAddress("foo", 555)),
+    Configuration conf = new Configuration();
+    assertEquals(NameNode.getUri(conf, new InetSocketAddress("foo", 555)),
                  URI.create("hdfs://foo:555"));
-    assertEquals(NameNode.getUri(new InetSocketAddress("foo",
+    assertEquals(NameNode.getUri(conf, new InetSocketAddress("foo",
                                                        NameNode.DEFAULT_PORT)),
                  URI.create("hdfs://foo"));
   }

src/test/org/apache/hadoop/mapred/TestMiniMRWithDFS.java

@@ -336,7 +336,7 @@ public class TestMiniMRWithDFS extends TestCase {
       TestResult result;
       final Path inDir = new Path("./wc/input");
       final Path outDir = new Path("hdfs://" +
-          dfs.getNameNode().getNameNodeAddress().getHostName() +
+          dfs.getNameNode().getNamenodeHostName(conf) +
           ":" + NameNode.DEFAULT_PORT +"/./wc/output");
       String input = "The quick brown fox\nhas many silly\nred fox sox\n";
       result = launchWordCount(jobConf, inDir, outDir, input, 3, 1);

src/test/org/apache/hadoop/mapreduce/security/TestTokenCache.java

@@ -129,6 +129,7 @@ public class TestTokenCache {
   }
   
   private static MiniMRCluster mrCluster;
+  private static Configuration conf;
   private static MiniDFSCluster dfsCluster;
   private static final Path TEST_DIR = 
     new Path(System.getProperty("test.build.data","/tmp"), "sleepTest");
@@ -141,7 +142,7 @@ public class TestTokenCache {
   
   @BeforeClass
   public static void setUp() throws Exception {
-    Configuration conf = new Configuration();
+    conf = new Configuration();
     dfsCluster = new MiniDFSCluster(conf, numSlaves, true, null);
     jConf = new JobConf(conf);
     mrCluster = new MiniMRCluster(0, 0, numSlaves, 
@@ -215,7 +216,7 @@ public class TestTokenCache {
     // provide namenodes names for the job to get the delegation tokens for
     //String nnUri = dfsCluster.getNameNode().getUri(namenode).toString();
     NameNode nn = dfsCluster.getNameNode();
-    URI nnUri = NameNode.getUri(nn.getNameNodeAddress());
+    URI nnUri = NameNode.getUri(conf, nn.getNameNodeAddress());
     jConf.set(JobContext.JOB_NAMENODES, nnUri + "," + nnUri.toString());
     // job tracker principle id..
     jConf.set(JobTracker.JT_USER_NAME, "jt_id");

src/webapps/hdfs/corrupt_files.jsp

@@ -25,14 +25,17 @@
 	import="org.apache.hadoop.fs.Path"
 	import="java.util.Collection"
 	import="java.util.Arrays" %>
+<%@ page import="org.apache.hadoop.hdfs.server.namenode.NameNode" %>
+<%@ page import="org.apache.hadoop.hdfs.server.namenode.FSNamesystem" %>
+<%@ page import="org.apache.hadoop.hdfs.server.namenode.JspHelper" %>
+<%@ page import="org.apache.hadoop.conf.Configuration" %>
 <%!//for java.io.Serializable
   private static final long serialVersionUID = 1L;%>
 <%
   NameNode nn = (NameNode) application.getAttribute("name.node");
   FSNamesystem fsn = nn.getNamesystem();
-  // String namenodeRole = nn.getRole().toString();
-  String namenodeLabel = nn.getNameNodeAddress().getHostName() + ":"
-      + nn.getNameNodeAddress().getPort();
+  Configuration conf = (Configuration) getServletContext().getAttribute(JspHelper.CURRENT_CONF);
+  String namenodeLabel = nn.getNamenodeHostName(conf) + ":" + nn.getNameNodeAddress().getPort();
   Collection<FSNamesystem.CorruptFileBlockInfo> corruptFileBlocks = 
 	fsn.listCorruptFileBlocks();
   int corruptFileCount = corruptFileBlocks.size();

src/webapps/hdfs/dfshealth.jsp

@@ -32,6 +32,7 @@
   import="java.lang.Math"
   import="java.net.URLEncoder"
 %>
+<%@ page import="org.apache.hadoop.conf.Configuration" %>
 <%!
   JspHelper jspHelper = new JspHelper();
 
@@ -248,9 +249,10 @@
   }%>
 
 <%
-  NameNode nn = (NameNode)application.getAttribute("name.node");
-  FSNamesystem fsn = nn.getNamesystem();
-  String namenodeLabel = nn.getNameNodeAddress().getHostName() + ":" + nn.getNameNodeAddress().getPort();
+    NameNode nn = (NameNode)application.getAttribute("name.node");
+    Configuration conf = (Configuration) getServletContext().getAttribute(JspHelper.CURRENT_CONF);
+    FSNamesystem fsn = nn.getNamesystem();
+    String namenodeLabel = nn.getNamenodeHostName(conf) + ":" + nn.getNameNodeAddress().getPort();
 %>
 
 <!DOCTYPE html>

src/webapps/hdfs/dfsnodelist.jsp

@@ -31,6 +31,7 @@
 	import="java.lang.Math"
 	import="java.net.URLEncoder"
 %>
+<%@ page import="org.apache.hadoop.conf.Configuration" %>
 <%!
 	JspHelper jspHelper = new JspHelper();
 
@@ -324,8 +325,9 @@ throws IOException {
 
 <%
 NameNode nn = (NameNode)application.getAttribute("name.node");
+Configuration conf = (Configuration) getServletContext().getAttribute(JspHelper.CURRENT_CONF);
 FSNamesystem fsn = nn.getNamesystem();
-String namenodeLabel = nn.getNameNodeAddress().getHostName() + ":" + nn.getNameNodeAddress().getPort();
+String namenodeLabel = nn.getNamenodeHostName(conf) + ":" + nn.getNameNodeAddress().getPort();
 %>
 
 <!DOCTYPE html>