svn commit: r1162279 [2/3] - in /hadoop/common/branches/HDFS-1623/hadoop-hdfs-project: ./ dev-support/ hadoop-hdfs/ hadoop-hdfs/.eclipse.templates/ hadoop-hdfs/.eclipse.templates/.launches/ hadoop-hdfs/dev-support/ hadoop-hdfs/dev-support/jdiff/ hadoop...

[to...@apache.org]

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/
------------------------------------------------------------------------------
--- svn:ignore (added)
+++ svn:ignore Fri Aug 26 22:46:17 2011
@@ -0,0 +1,10 @@
+build
+build-fi
+build.properties
+logs
+.classpath
+.externalToolBuilders
+.launches
+.project
+.settings
+target

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/
------------------------------------------------------------------------------
--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,5 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs:1152502-1162221
+/hadoop/core/branches/branch-0.19/hdfs:713112
+/hadoop/hdfs/branches/HDFS-1052:987665-1095512
+/hadoop/hdfs/branches/HDFS-265:796829-820463
+/hadoop/hdfs/branches/branch-0.21:820487

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt Fri Aug 26 22:46:17 2011
@@ -0,0 +1,9 @@
+Changes for HDFS-1623 branch.
+
+This change list will be merged into the trunk CHANGES.txt when the HDFS-1623
+branch is merged.
+------------------------------
+
+HDFS-2179. Add fencing framework and mechanisms for NameNode HA. (todd)
+
+HDFS-1974. Introduce active and standy states to the namenode. (suresh)

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/ivy/
------------------------------------------------------------------------------
--- svn:ignore (added)
+++ svn:ignore Fri Aug 26 22:46:17 2011
@@ -0,0 +1,4 @@
+hadoop-hdfs.xml
+hadoop-hdfs-test.xml
+ivy-*.jar
+maven-ant-tasks*.jar

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/pom.xml (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/pom.xml)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/pom.xml?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/pom.xml&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/pom.xml&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/pom.xml (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/pom.xml Fri Aug 26 22:46:17 2011
@@ -109,6 +109,10 @@
       <artifactId>ant</artifactId>
       <scope>provided</scope>
     </dependency>
+    <dependency>
+      <groupId>com.jcraft</groupId>
+      <artifactId>jsch</artifactId>
+    </dependency>
   </dependencies>
 
   <build>
@@ -277,6 +281,7 @@
         <configuration>
           <excludes>
             <exclude>CHANGES.txt</exclude>
+            <exclude>CHANGES.HDFS-1623.txt</exclude>
             <exclude>.idea/**</exclude>
             <exclude>src/main/conf/*</exclude>
             <exclude>src/main/docs/**</exclude>

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/conf/
------------------------------------------------------------------------------
--- svn:ignore (added)
+++ svn:ignore Fri Aug 26 22:46:17 2011
@@ -0,0 +1,10 @@
+masters
+slaves
+hadoop-env.sh
+hadoop-site.xml
+core-site.xml
+mapred-site.xml
+hdfs-site.xml
+hadoop-policy.xml
+capacity-scheduler.xml
+mapred-queue-acls.xml

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/docs/
------------------------------------------------------------------------------
--- svn:ignore (added)
+++ svn:ignore Fri Aug 26 22:46:17 2011
@@ -0,0 +1 @@
+build

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/
------------------------------------------------------------------------------
--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,10 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java:1159757-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/java:713112
+/hadoop/core/branches/branch-0.19/hdfs/src/main/java:713112
+/hadoop/core/trunk/src/hdfs:776175-785643,785929-786278
+/hadoop/hdfs/branches/HDFS-1052/src/java:987665-1095512
+/hadoop/hdfs/branches/HDFS-1052/src/main/java:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/java:796829-820463
+/hadoop/hdfs/branches/HDFS-265/src/main/java:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/java:820487
+/hadoop/hdfs/branches/branch-0.21/src/main/java:820487

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSUtil.java Fri Aug 26 22:46:17 2011
@@ -696,4 +696,14 @@ public class DFSUtil {
         ClientDatanodeProtocol.versionID, addr, ticket, confWithNoIpcIdle,
         NetUtils.getDefaultSocketFactory(conf), socketTimeout);
   }
+
+  /**
+   * Returns true if HA for namenode is configured.
+   * @param conf Configuration
+   * @return true if HA is configured in the configuration; else false.
+   */
+  public static boolean isHAEnabled(Configuration conf) {
+    // TODO:HA configuration changes pending
+    return false;
+  }
 }

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/BackupNode.java Fri Aug 26 22:46:17 2011
@@ -189,34 +189,6 @@ public class BackupNode extends NameNode
   }
 
   /////////////////////////////////////////////////////
-  // NamenodeProtocol implementation for backup node.
-  /////////////////////////////////////////////////////
-  @Override // NamenodeProtocol
-  public BlocksWithLocations getBlocks(DatanodeInfo datanode, long size)
-  throws IOException {
-    throw new UnsupportedActionException("getBlocks");
-  }
-
-  // Only active name-node can register other nodes.
-  @Override // NamenodeProtocol
-  public NamenodeRegistration register(NamenodeRegistration registration
-  ) throws IOException {
-    throw new UnsupportedActionException("register");
-  }
-
-  @Override // NamenodeProtocol
-  public NamenodeCommand startCheckpoint(NamenodeRegistration registration)
-  throws IOException {
-    throw new UnsupportedActionException("startCheckpoint");
-  }
-
-  @Override // NamenodeProtocol
-  public void endCheckpoint(NamenodeRegistration registration,
-                            CheckpointSignature sig) throws IOException {
-    throw new UnsupportedActionException("endCheckpoint");
-  }  
-
-  /////////////////////////////////////////////////////
   // BackupNodeProtocol implementation for backup node.
   /////////////////////////////////////////////////////
 
@@ -224,6 +196,7 @@ public class BackupNode extends NameNode
   public void journal(NamenodeRegistration nnReg,
       long firstTxId, int numTxns,
       byte[] records) throws IOException {
+    checkOperation(OperationCategory.JOURNAL);
     verifyRequest(nnReg);
     if(!nnRpcAddress.equals(nnReg.getAddress()))
       throw new IOException("Journal request from unexpected name-node: "
@@ -234,6 +207,7 @@ public class BackupNode extends NameNode
   @Override
   public void startLogSegment(NamenodeRegistration registration, long txid)
       throws IOException {
+    checkOperation(OperationCategory.JOURNAL);
     verifyRequest(registration);
   
     getBNImage().namenodeStartedLogSegment(txid);
@@ -369,4 +343,14 @@ public class BackupNode extends NameNode
   String getClusterId() {
     return clusterId;
   }
+  
+  @Override // NameNode
+  protected void checkOperation(OperationCategory op)
+      throws UnsupportedActionException {
+    if (OperationCategory.JOURNAL != op) {
+      String msg = "Operation category " + op
+          + " is not supported at the BackupNode";
+      throw new UnsupportedActionException(msg);
+    }
+  }
 }

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNode.java Fri Aug 26 22:46:17 2011
@@ -31,6 +31,8 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.ha.HealthCheckFailedException;
+import org.apache.hadoop.ha.ServiceFailedException;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.fs.ContentSummary;
 import org.apache.hadoop.fs.CreateFlag;
@@ -72,11 +74,15 @@ import org.apache.hadoop.hdfs.server.com
 import org.apache.hadoop.hdfs.server.common.HdfsConstants.StartupOption;
 import org.apache.hadoop.hdfs.server.common.IncorrectVersionException;
 import org.apache.hadoop.hdfs.server.common.UpgradeStatusReport;
+import org.apache.hadoop.hdfs.server.namenode.ha.ActiveState;
+import org.apache.hadoop.hdfs.server.namenode.ha.HAState;
+import org.apache.hadoop.hdfs.server.namenode.ha.StandbyState;
 import org.apache.hadoop.hdfs.server.namenode.metrics.NameNodeMetrics;
 import org.apache.hadoop.hdfs.server.protocol.BlocksWithLocations;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeCommand;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeProtocol;
 import org.apache.hadoop.hdfs.server.protocol.DatanodeRegistration;
+import org.apache.hadoop.hdfs.server.protocol.JournalProtocol;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeCommand;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocol;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
@@ -152,6 +158,20 @@ public class NameNode implements Namenod
   }
   
   /**
+   * Categories of operations supported by the namenode.
+   */
+  public static enum OperationCategory {
+    /** Read operation that does not change the namespace state */
+    READ,
+    /** Write operation that changes the namespace state */
+    WRITE,
+    /** Operations related to checkpointing */
+    CHECKPOINT,
+    /** Operations related to {@link JournalProtocol} */
+    JOURNAL
+  }
+  
+  /**
    * HDFS federation configuration can have two types of parameters:
    * <ol>
    * <li>Parameter that is common for all the name services in the cluster.</li>
@@ -210,9 +230,15 @@ public class NameNode implements Namenod
 
   public static final Log LOG = LogFactory.getLog(NameNode.class.getName());
   public static final Log stateChangeLog = LogFactory.getLog("org.apache.hadoop.hdfs.StateChange");
+  public static final HAState ACTIVE_STATE = new ActiveState();
+  public static final HAState STANDBY_STATE = new StandbyState();
   
   protected FSNamesystem namesystem; 
   protected NamenodeRole role;
+  private HAState state;
+  private final boolean haEnabled;
+
+  
   /** RPC server. Package-protected for use in tests. */
   Server server;
   /** RPC server for HDFS Services communication.
@@ -408,6 +434,7 @@ public class NameNode implements Namenod
    * @param conf the configuration
    */
   protected void initialize(Configuration conf) throws IOException {
+    initializeGenericKeys(conf);
     InetSocketAddress socAddr = getRpcServerAddress(conf);
     UserGroupInformation.setConfiguration(conf);
     loginAsNameNodeUser(conf);
@@ -456,10 +483,6 @@ public class NameNode implements Namenod
     }
 
     activate(conf);
-    LOG.info(getRole() + " up at: " + rpcAddress);
-    if (serviceRPCAddress != null) {
-      LOG.info(getRole() + " service server is up at: " + serviceRPCAddress); 
-    }
   }
   
   /**
@@ -509,6 +532,10 @@ public class NameNode implements Namenod
         LOG.warn("ServicePlugin " + p + " could not be started", t);
       }
     }
+    LOG.info(getRole() + " up at: " + rpcAddress);
+    if (serviceRPCAddress != null) {
+      LOG.info(getRole() + " service server is up at: " + serviceRPCAddress); 
+    }
   }
 
   private void startTrashEmptier(Configuration conf) throws IOException {
@@ -562,8 +589,9 @@ public class NameNode implements Namenod
   protected NameNode(Configuration conf, NamenodeRole role) 
       throws IOException { 
     this.role = role;
+    this.haEnabled = DFSUtil.isHAEnabled(conf);
+    this.state = !haEnabled ? ACTIVE_STATE : STANDBY_STATE;
     try {
-      initializeGenericKeys(conf);
       initialize(conf);
     } catch (IOException e) {
       this.stop();
@@ -644,6 +672,7 @@ public class NameNode implements Namenod
   public void errorReport(NamenodeRegistration registration,
                           int errorCode, 
                           String msg) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     verifyRequest(registration);
     LOG.info("Error report from " + registration + ": " + msg);
     if(errorCode == FATAL)
@@ -671,27 +700,28 @@ public class NameNode implements Namenod
   @Override // NamenodeProtocol
   public void endCheckpoint(NamenodeRegistration registration,
                             CheckpointSignature sig) throws IOException {
-    verifyRequest(registration);
-    if(!isRole(NamenodeRole.NAMENODE))
-      throw new IOException("Only an ACTIVE node can invoke endCheckpoint.");
+    checkOperation(OperationCategory.CHECKPOINT);
     namesystem.endCheckpoint(registration, sig);
   }
 
   @Override // ClientProtocol
   public Token<DelegationTokenIdentifier> getDelegationToken(Text renewer)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     return namesystem.getDelegationToken(renewer);
   }
 
   @Override // ClientProtocol
   public long renewDelegationToken(Token<DelegationTokenIdentifier> token)
       throws InvalidToken, IOException {
+    checkOperation(OperationCategory.WRITE);
     return namesystem.renewDelegationToken(token);
   }
 
   @Override // ClientProtocol
   public void cancelDelegationToken(Token<DelegationTokenIdentifier> token)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.cancelDelegationToken(token);
   }
   
@@ -700,6 +730,7 @@ public class NameNode implements Namenod
                                           long offset, 
                                           long length) 
       throws IOException {
+    checkOperation(OperationCategory.READ);
     metrics.incrGetBlockLocations();
     return namesystem.getBlockLocations(getClientMachine(), 
                                         src, offset, length);
@@ -718,6 +749,7 @@ public class NameNode implements Namenod
                      boolean createParent,
                      short replication,
                      long blockSize) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     String clientMachine = getClientMachine();
     if (stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.create: file "
@@ -738,6 +770,7 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public LocatedBlock append(String src, String clientName) 
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     String clientMachine = getClientMachine();
     if (stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.append: file "
@@ -750,6 +783,7 @@ public class NameNode implements Namenod
 
   @Override // ClientProtocol
   public boolean recoverLease(String src, String clientName) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     String clientMachine = getClientMachine();
     return namesystem.recoverLease(src, clientName, clientMachine);
   }
@@ -757,18 +791,21 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public boolean setReplication(String src, short replication) 
     throws IOException {  
+    checkOperation(OperationCategory.WRITE);
     return namesystem.setReplication(src, replication);
   }
     
   @Override // ClientProtocol
   public void setPermission(String src, FsPermission permissions)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.setPermission(src, permissions);
   }
 
   @Override // ClientProtocol
   public void setOwner(String src, String username, String groupname)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.setOwner(src, username, groupname);
   }
 
@@ -778,6 +815,7 @@ public class NameNode implements Namenod
                                ExtendedBlock previous,
                                DatanodeInfo[] excludedNodes)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*BLOCK* NameNode.addBlock: file "
           +src+" for "+clientName);
@@ -801,6 +839,7 @@ public class NameNode implements Namenod
       final DatanodeInfo[] existings, final DatanodeInfo[] excludes,
       final int numAdditionalNodes, final String clientName
       ) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if (LOG.isDebugEnabled()) {
       LOG.debug("getAdditionalDatanode: src=" + src
           + ", blk=" + blk
@@ -826,8 +865,10 @@ public class NameNode implements Namenod
   /**
    * The client needs to give up on the block.
    */
+  @Override // ClientProtocol
   public void abandonBlock(ExtendedBlock b, String src, String holder)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*BLOCK* NameNode.abandonBlock: "
           +b+" of file "+src);
@@ -840,6 +881,7 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public boolean complete(String src, String clientName, ExtendedBlock last)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.complete: "
           + src + " for " + clientName);
@@ -853,8 +895,9 @@ public class NameNode implements Namenod
    * mark the block as corrupt.  In the future we might 
    * check the blocks are actually corrupt. 
    */
-  @Override
+  @Override // ClientProtocol, DatanodeProtocol
   public void reportBadBlocks(LocatedBlock[] blocks) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     stateChangeLog.info("*DIR* NameNode.reportBadBlocks");
     for (int i = 0; i < blocks.length; i++) {
       ExtendedBlock blk = blocks[i].getBlock();
@@ -869,6 +912,7 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public LocatedBlock updateBlockForPipeline(ExtendedBlock block, String clientName)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     return namesystem.updateBlockForPipeline(block, clientName);
   }
 
@@ -877,6 +921,7 @@ public class NameNode implements Namenod
   public void updatePipeline(String clientName, ExtendedBlock oldBlock,
       ExtendedBlock newBlock, DatanodeID[] newNodes)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.updatePipeline(clientName, oldBlock, newBlock, newNodes);
   }
   
@@ -885,6 +930,7 @@ public class NameNode implements Namenod
       long newgenerationstamp, long newlength,
       boolean closeFile, boolean deleteblock, DatanodeID[] newtargets)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.commitBlockSynchronization(block,
         newgenerationstamp, newlength, closeFile, deleteblock, newtargets);
   }
@@ -892,12 +938,14 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public long getPreferredBlockSize(String filename) 
       throws IOException {
+    checkOperation(OperationCategory.READ);
     return namesystem.getPreferredBlockSize(filename);
   }
     
   @Deprecated
   @Override // ClientProtocol
   public boolean rename(String src, String dst) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.rename: " + src + " to " + dst);
     }
@@ -914,12 +962,14 @@ public class NameNode implements Namenod
   
   @Override // ClientProtocol
   public void concat(String trg, String[] src) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.concat(trg, src);
   }
   
   @Override // ClientProtocol
   public void rename(String src, String dst, Options.Rename... options)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.rename: " + src + " to " + dst);
     }
@@ -934,11 +984,13 @@ public class NameNode implements Namenod
   @Deprecated
   @Override // ClientProtocol
   public boolean delete(String src) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     return delete(src, true);
   }
 
   @Override // ClientProtocol
   public boolean delete(String src, boolean recursive) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if (stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* Namenode.delete: src=" + src
           + ", recursive=" + recursive);
@@ -963,6 +1015,7 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public boolean mkdirs(String src, FsPermission masked, boolean createParent)
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     if(stateChangeLog.isDebugEnabled()) {
       stateChangeLog.debug("*DIR* NameNode.mkdirs: " + src);
     }
@@ -977,13 +1030,14 @@ public class NameNode implements Namenod
 
   @Override // ClientProtocol
   public void renewLease(String clientName) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.renewLease(clientName);        
   }
 
   @Override // ClientProtocol
   public DirectoryListing getListing(String src, byte[] startAfter,
-      boolean needLocation)
-  throws IOException {
+      boolean needLocation) throws IOException {
+    checkOperation(OperationCategory.READ);
     DirectoryListing files = namesystem.getListing(
         src, startAfter, needLocation);
     if (files != null) {
@@ -995,12 +1049,14 @@ public class NameNode implements Namenod
 
   @Override // ClientProtocol
   public HdfsFileStatus getFileInfo(String src)  throws IOException {
+    checkOperation(OperationCategory.READ);
     metrics.incrFileInfoOps();
     return namesystem.getFileInfo(src, true);
   }
 
   @Override // ClientProtocol
   public HdfsFileStatus getFileLinkInfo(String src) throws IOException { 
+    checkOperation(OperationCategory.READ);
     metrics.incrFileInfoOps();
     return namesystem.getFileInfo(src, false);
   }
@@ -1013,6 +1069,7 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public DatanodeInfo[] getDatanodeReport(DatanodeReportType type)
       throws IOException {
+    checkOperation(OperationCategory.READ);
     DatanodeInfo results[] = namesystem.datanodeReport(type);
     if (results == null ) {
       throw new IOException("Cannot find datanode report");
@@ -1022,6 +1079,7 @@ public class NameNode implements Namenod
     
   @Override // ClientProtocol
   public boolean setSafeMode(SafeModeAction action) throws IOException {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.setSafeMode(action);
   }
 
@@ -1035,55 +1093,65 @@ public class NameNode implements Namenod
   @Override // ClientProtocol
   public boolean restoreFailedStorage(String arg) 
       throws AccessControlException {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.restoreFailedStorage(arg);
   }
 
   @Override // ClientProtocol
   public void saveNamespace() throws IOException {
+    // TODO:HA decide on OperationCategory for this
     namesystem.saveNamespace();
   }
 
   @Override // ClientProtocol
   public void refreshNodes() throws IOException {
+    // TODO:HA decide on OperationCategory for this
     namesystem.getBlockManager().getDatanodeManager().refreshNodes(
         new HdfsConfiguration());
   }
 
   @Override // NamenodeProtocol
   public long getTransactionID() {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.getEditLog().getSyncTxId();
   }
 
   @Override // NamenodeProtocol
   public CheckpointSignature rollEditLog() throws IOException {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.rollEditLog();
   }
   
-  @Override
+  @Override // NamenodeProtocol
   public RemoteEditLogManifest getEditLogManifest(long sinceTxId)
   throws IOException {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.getEditLog().getEditLogManifest(sinceTxId);
   }
     
   @Override // ClientProtocol
   public void finalizeUpgrade() throws IOException {
+    // TODO:HA decide on OperationCategory for this
     namesystem.finalizeUpgrade();
   }
 
   @Override // ClientProtocol
   public UpgradeStatusReport distributedUpgradeProgress(UpgradeAction action)
       throws IOException {
+    // TODO:HA decide on OperationCategory for this
     return namesystem.distributedUpgradeProgress(action);
   }
 
   @Override // ClientProtocol
   public void metaSave(String filename) throws IOException {
+    // TODO:HA decide on OperationCategory for this
     namesystem.metaSave(filename);
   }
 
   @Override // ClientProtocol
   public CorruptFileBlocks listCorruptFileBlocks(String path, String cookie)
       throws IOException {
+    checkOperation(OperationCategory.READ);
     Collection<FSNamesystem.CorruptFileBlockInfo> fbs =
       namesystem.listCorruptFileBlocks(path, cookie);
     
@@ -1105,34 +1173,40 @@ public class NameNode implements Namenod
    */
   @Override // ClientProtocol
   public void setBalancerBandwidth(long bandwidth) throws IOException {
+    // TODO:HA decide on OperationCategory for this
     namesystem.getBlockManager().getDatanodeManager().setBalancerBandwidth(bandwidth);
   }
   
   @Override // ClientProtocol
   public ContentSummary getContentSummary(String path) throws IOException {
+    checkOperation(OperationCategory.READ);
     return namesystem.getContentSummary(path);
   }
 
   @Override // ClientProtocol
   public void setQuota(String path, long namespaceQuota, long diskspaceQuota) 
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.setQuota(path, namespaceQuota, diskspaceQuota);
   }
   
   @Override // ClientProtocol
   public void fsync(String src, String clientName) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.fsync(src, clientName);
   }
 
   @Override // ClientProtocol
   public void setTimes(String src, long mtime, long atime) 
       throws IOException {
+    checkOperation(OperationCategory.WRITE);
     namesystem.setTimes(src, mtime, atime);
   }
 
   @Override // ClientProtocol
   public void createSymlink(String target, String link, FsPermission dirPerms,
       boolean createParent) throws IOException {
+    checkOperation(OperationCategory.WRITE);
     metrics.incrCreateSymlinkOps();
     /* We enforce the MAX_PATH_LENGTH limit even though a symlink target 
      * URI may refer to a non-HDFS file system. 
@@ -1152,6 +1226,7 @@ public class NameNode implements Namenod
 
   @Override // ClientProtocol
   public String getLinkTarget(String path) throws IOException {
+    checkOperation(OperationCategory.READ);
     metrics.incrGetLinkTargetOps();
     /* Resolves the first symlink in the given path, returning a
      * new path consisting of the target of the symlink and any 
@@ -1599,4 +1674,43 @@ public class NameNode implements Namenod
     }
     return clientMachine;
   }
+  
+  @Override // HAServiceProtocol
+  public synchronized void monitorHealth() throws HealthCheckFailedException {
+    if (!haEnabled) {
+      return; // no-op, if HA is not eanbled
+    }
+    // TODO:HA implement health check
+    return;
+  }
+  
+  @Override // HAServiceProtocol
+  public synchronized void transitionToActive() throws ServiceFailedException {
+    if (!haEnabled) {
+      throw new ServiceFailedException("HA for namenode is not enabled");
+    }
+    state.setState(this, ACTIVE_STATE);
+  }
+  
+  @Override // HAServiceProtocol
+  public synchronized void transitionToStandby() throws ServiceFailedException {
+    if (!haEnabled) {
+      throw new ServiceFailedException("HA for namenode is not enabled");
+    }
+    state.setState(this, STANDBY_STATE);
+  }
+  
+  /** Check if an operation of given category is allowed */
+  protected synchronized void checkOperation(final OperationCategory op)
+      throws UnsupportedActionException {
+    state.checkOperation(this, op);
+  }
+  
+  public synchronized HAState getState() {
+    return state;
+  }
+  
+  public synchronized void setState(final HAState s) {
+    state = s;
+  }
 }

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/UnsupportedActionException.java Fri Aug 26 22:46:17 2011
@@ -32,8 +32,7 @@ public class UnsupportedActionException 
   /** for java.io.Serializable */
   private static final long serialVersionUID = 1L;
 
-  public UnsupportedActionException(String action) {
-    super("Action " + action + "() is not supported.");
+  public UnsupportedActionException(String msg) {
+    super(msg);
   }
-
 }

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ActiveState.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ActiveState.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ActiveState.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ActiveState.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,59 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import org.apache.hadoop.ha.ServiceFailedException;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.hdfs.server.namenode.NameNode.OperationCategory;
+import org.apache.hadoop.hdfs.server.namenode.UnsupportedActionException;
+
+/**
+ * Active state of the namenode. In this state, namenode provides the namenode
+ * service and handles operations of type {@link OperationCategory#WRITE} and
+ * {@link OperationCategory#READ}.
+ */
+public class ActiveState extends HAState {
+  public ActiveState() {
+    super("active");
+  }
+
+  @Override
+  public void checkOperation(NameNode nn, OperationCategory op)
+      throws UnsupportedActionException {
+    return; // Other than journal all operations are allowed in active state
+  }
+  
+  @Override
+  public void setState(NameNode nn, HAState s) throws ServiceFailedException {
+    if (s == NameNode.STANDBY_STATE) {
+      setStateInternal(nn, s);
+      return;
+    }
+    super.setState(nn, s);
+  }
+
+  @Override
+  protected void enterState(NameNode nn) throws ServiceFailedException {
+    // TODO:HA
+  }
+
+  @Override
+  protected void exitState(NameNode nn) throws ServiceFailedException {
+    // TODO:HA
+  }
+}

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/BadFencingConfigurationException.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/BadFencingConfigurationException.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/BadFencingConfigurationException.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/BadFencingConfigurationException.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,36 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import java.io.IOException;
+
+/**
+ * Indicates that the operator has specified an invalid configuration
+ * for fencing methods.
+ */
+class BadFencingConfigurationException extends IOException {
+  private static final long serialVersionUID = 1L;
+
+  public BadFencingConfigurationException(String msg) {
+    super(msg);
+  }
+
+  public BadFencingConfigurationException(String msg, Throwable cause) {
+    super(msg, cause);
+  }
+}
\ No newline at end of file

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/FenceMethod.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/FenceMethod.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/FenceMethod.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/FenceMethod.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,63 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.conf.Configurable;
+
+/**
+ * A fencing method is a method by which one node can forcibly prevent
+ * another node from making continued progress. This might be implemented
+ * by killing a process on the other node, by denying the other node's
+ * access to shared storage, or by accessing a PDU to cut the other node's
+ * power.
+ * <p>
+ * Since these methods are often vendor- or device-specific, operators
+ * may implement this interface in order to achieve fencing.
+ * <p>
+ * Fencing is configured by the operator as an ordered list of methods to
+ * attempt. Each method will be tried in turn, and the next in the list
+ * will only be attempted if the previous one fails. See {@link NodeFencer}
+ * for more information.
+ * <p>
+ * If an implementation also implements {@link Configurable} then its
+ * <code>setConf</code> method will be called upon instantiation.
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Unstable
+public interface FenceMethod {
+  /**
+   * Verify that the given fencing method's arguments are valid.
+   * @param args the arguments provided in the configuration. This may
+   *        be null if the operator did not configure any arguments.
+   * @throws BadFencingConfigurationException if the arguments are invalid
+   */
+  public void checkArgs(String args) throws BadFencingConfigurationException;
+  
+  /**
+   * Attempt to fence the target node.
+   * @param args the configured arguments, which were checked at startup by
+   *             {@link #checkArgs(String)}
+   * @return true if fencing was successful, false if unsuccessful or
+   *              indeterminate
+   * @throws BadFencingConfigurationException if the configuration was
+   *         determined to be invalid only at runtime
+   */
+  public boolean tryFence(String args) throws BadFencingConfigurationException; 
+}
\ No newline at end of file

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/HAState.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/HAState.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/HAState.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/HAState.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,104 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.ha.ServiceFailedException;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.hdfs.server.namenode.NameNode.OperationCategory;
+import org.apache.hadoop.hdfs.server.namenode.UnsupportedActionException;
+
+/**
+ * Namenode base state to implement state machine pattern.
+ */
+@InterfaceAudience.Private
+abstract public class HAState {
+  protected final String name;
+
+  /**
+   * Constructor
+   * @param name Name of the state.
+   */
+  public HAState(String name) {
+    this.name = name;
+  }
+
+  /**
+   * Internal method to transition the state of a given namenode to a new state.
+   * @param nn Namenode
+   * @param s new state
+   * @throws ServiceFailedException on failure to transition to new state.
+   */
+  protected final void setStateInternal(final NameNode nn, final HAState s)
+      throws ServiceFailedException {
+    exitState(nn);
+    nn.setState(s);
+    s.enterState(nn);
+  }
+
+  /**
+   * Method to be overridden by subclasses to perform steps necessary for
+   * entering a state.
+   * @param nn Namenode
+   * @throws ServiceFailedException on failure to enter the state.
+   */
+  protected abstract void enterState(final NameNode nn)
+      throws ServiceFailedException;
+
+  /**
+   * Method to be overridden by subclasses to perform steps necessary for
+   * exiting a state.
+   * @param nn Namenode
+   * @throws ServiceFailedException on failure to enter the state.
+   */
+  protected abstract void exitState(final NameNode nn)
+      throws ServiceFailedException;
+
+  /**
+   * Move from the existing state to a new state
+   * @param nn Namenode
+   * @param s new state
+   * @throws ServiceFailedException on failure to transition to new state.
+   */
+  public void setState(NameNode nn, HAState s) throws ServiceFailedException {
+    if (this == s) { // Aleady in the new state
+      return;
+    }
+    throw new ServiceFailedException("Transtion from state " + this + " to "
+        + s + " is not allowed.");
+  }
+  
+  /**
+   * Check if an operation is supported in a given state.
+   * @param nn Namenode
+   * @param op Type of the operation.
+   * @throws UnsupportedActionException if a given type of operation is not
+   *           supported in this state.
+   */
+  public void checkOperation(final NameNode nn, final OperationCategory op)
+      throws UnsupportedActionException {
+    String msg = "Operation category " + op + " is not supported in state "
+        + nn.getState();
+    throw new UnsupportedActionException(msg);
+  }
+  
+  @Override
+  public String toString() {
+    return super.toString();
+  }
+}
\ No newline at end of file

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/NodeFencer.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/NodeFencer.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/NodeFencer.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/NodeFencer.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,186 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import java.util.List;
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.util.ReflectionUtils;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.Lists;
+
+/**
+ * This class parses the configured list of fencing methods, and
+ * is responsible for trying each one in turn while logging informative
+ * output.<p>
+ * 
+ * The fencing methods are configured as a carriage-return separated list.
+ * Each line in the list is of the form:<p>
+ * <code>com.example.foo.MyMethod(arg string)</code>
+ * or
+ * <code>com.example.foo.MyMethod</code>
+ * The class provided must implement the {@link FenceMethod} interface.
+ * The fencing methods that ship with Hadoop may also be referred to
+ * by shortened names:<p>
+ * <ul>
+ * <li><code>shell(/path/to/some/script.sh args...)</code></li>
+ * <li><code>sshfence(...)</code> (see {@link SshFenceByTcpPort})
+ * </ul>
+ */
+@InterfaceAudience.Private
+@InterfaceStability.Evolving
+public class NodeFencer {
+  static final String CONF_METHODS_KEY =
+    "dfs.namenode.ha.fencing.methods";
+  
+  private static final String CLASS_RE = "([a-zA-Z0-9\\.\\$]+)";
+  private static final Pattern CLASS_WITH_ARGUMENT =
+    Pattern.compile(CLASS_RE + "\\((.+?)\\)");
+  private static final Pattern CLASS_WITHOUT_ARGUMENT =
+    Pattern.compile(CLASS_RE);
+  private static final Pattern HASH_COMMENT_RE =
+    Pattern.compile("#.*$");
+
+  private static final Log LOG = LogFactory.getLog(NodeFencer.class);
+
+  /**
+   * Standard fencing methods included with HDFS.
+   */
+  private static final Map<String, Class<? extends FenceMethod>> STANDARD_METHODS =
+    ImmutableMap.<String, Class<? extends FenceMethod>>of(
+        "shell", ShellCommandFencer.class,
+        "sshfence", SshFenceByTcpPort.class);
+  
+  private final List<FenceMethodWithArg> methods;
+  
+  public NodeFencer(Configuration conf)
+      throws BadFencingConfigurationException {
+    this.methods = parseMethods(conf);
+  }
+  
+  public boolean fence() {
+    LOG.info("====== Beginning NameNode Fencing Process... ======");
+    int i = 0;
+    for (FenceMethodWithArg method : methods) {
+      LOG.info("Trying method " + (++i) + "/" + methods.size() +": " + method);
+      
+      try {
+        if (method.method.tryFence(method.arg)) {
+          LOG.info("====== Fencing successful by method " + method + " ======");
+          return true;
+        }
+      } catch (BadFencingConfigurationException e) {
+        LOG.error("Fencing method " + method + " misconfigured", e);
+        continue;
+      } catch (Throwable t) {
+        LOG.error("Fencing method " + method + " failed with an unexpected error.", t);
+        continue;
+      }
+      LOG.warn("Fencing method " + method + " was unsuccessful.");
+    }
+    
+    LOG.error("Unable to fence NameNode by any configured method.");
+    return false;
+  }
+
+  private static List<FenceMethodWithArg> parseMethods(Configuration conf)
+  throws BadFencingConfigurationException {
+    String confStr = conf.get(CONF_METHODS_KEY);
+    String[] lines = confStr.split("\\s*\n\\s*");
+    
+    List<FenceMethodWithArg> methods = Lists.newArrayList();
+    for (String line : lines) {
+      line = HASH_COMMENT_RE.matcher(line).replaceAll("");
+      line = line.trim();
+      if (!line.isEmpty()) {
+        methods.add(parseMethod(conf, line));
+      }
+    }
+    
+    return methods;
+  }
+
+  private static FenceMethodWithArg parseMethod(Configuration conf, String line)
+      throws BadFencingConfigurationException {
+    Matcher m;
+    if ((m = CLASS_WITH_ARGUMENT.matcher(line)).matches()) {
+      String className = m.group(1);
+      String arg = m.group(2);
+      
+      return createFenceMethod(conf, className, arg);
+    } else if ((m = CLASS_WITHOUT_ARGUMENT.matcher(line)).matches()) {
+      String className = m.group(1);
+      return createFenceMethod(conf, className, null);
+    } else {
+      throw new BadFencingConfigurationException(
+          "Unable to parse line: '" + line + "'");
+    }
+  }
+
+  private static FenceMethodWithArg createFenceMethod(
+      Configuration conf, String clazzName, String arg)
+      throws BadFencingConfigurationException {
+
+    Class<?> clazz;
+    try {
+      // See if it's a short name for one of the built-in methods
+      clazz = STANDARD_METHODS.get(clazzName);
+      if (clazz == null) {
+        // Try to instantiate the user's custom method
+        clazz = Class.forName(clazzName);
+      }
+    } catch (Exception e) {
+      throw new BadFencingConfigurationException(
+          "Could not find configured fencing method " + clazzName,
+          e);
+    }
+    
+    // Check that it implements the right interface
+    if (!FenceMethod.class.isAssignableFrom(clazz)) {
+      throw new BadFencingConfigurationException("Class " + clazzName +
+          " does not implement FenceMethod");
+    }
+    
+    FenceMethod method = (FenceMethod)ReflectionUtils.newInstance(
+        clazz, conf);
+    method.checkArgs(arg);
+    return new FenceMethodWithArg(method, arg);
+  }
+  
+  private static class FenceMethodWithArg {
+    private final FenceMethod method;
+    private final String arg;
+    
+    private FenceMethodWithArg(FenceMethod method, String arg) {
+      this.method = method;
+      this.arg = arg;
+    }
+    
+    public String toString() {
+      return method.getClass().getCanonicalName() + "(" + arg + ")";
+    }
+  }
+}

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ShellCommandFencer.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ShellCommandFencer.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ShellCommandFencer.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ShellCommandFencer.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,173 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import java.io.IOException;
+import java.lang.reflect.Field;
+import java.util.Map;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configured;
+
+import com.google.common.annotations.VisibleForTesting;
+
+/**
+ * Fencing method that runs a shell command. It should be specified
+ * in the fencing configuration like:<br>
+ * <code>
+ *   shell(/path/to/my/script.sh arg1 arg2 ...)
+ * </code><br>
+ * The string between '(' and ')' is passed directly to a bash shell and
+ * may not include any closing parentheses.<p>
+ * 
+ * The shell command will be run with an environment set up to contain
+ * all of the current Hadoop configuration variables, with the '_' character 
+ * replacing any '.' characters in the configuration keys.<p>
+ * 
+ * If the shell command returns an exit code of 0, the fencing is
+ * determined to be successful. If it returns any other exit code, the
+ * fencing was not successful and the next fencing method in the list
+ * will be attempted.<p>
+ * 
+ * <em>Note:</em> this fencing method does not implement any timeout.
+ * If timeouts are necessary, they should be implemented in the shell
+ * script itself (eg by forking a subshell to kill its parent in
+ * some number of seconds).
+ */
+public class ShellCommandFencer
+  extends Configured implements FenceMethod {
+
+  /** Length at which to abbreviate command in long messages */
+  private static final int ABBREV_LENGTH = 20;
+  
+  @VisibleForTesting
+  static Log LOG = LogFactory.getLog(
+      ShellCommandFencer.class);
+  
+  @Override
+  public void checkArgs(String args) throws BadFencingConfigurationException {
+    if (args == null || args.isEmpty()) {
+      throw new BadFencingConfigurationException(
+          "No argument passed to 'shell' fencing method");
+    }
+    // Nothing else we can really check without actually running the command
+  }
+
+  @Override
+  public boolean tryFence(String cmd) {
+    ProcessBuilder builder = new ProcessBuilder(
+        "bash", "-e", "-c", cmd);
+    setConfAsEnvVars(builder.environment());
+
+    Process p;
+    try {
+      p = builder.start();
+      p.getOutputStream().close();
+    } catch (IOException e) {
+      LOG.warn("Unable to execute " + cmd, e);
+      return false;
+    }
+    
+    String pid = tryGetPid(p);
+    LOG.info("Launched fencing command '" + cmd + "' with "
+        + ((pid != null) ? ("pid " + pid) : "unknown pid"));
+    
+    String logPrefix = abbreviate(cmd, ABBREV_LENGTH);
+    if (pid != null) {
+      logPrefix = "[PID " + pid + "] " + logPrefix;
+    }
+    
+    // Pump logs to stderr
+    StreamPumper errPumper = new StreamPumper(
+        LOG, logPrefix, p.getErrorStream(),
+        StreamPumper.StreamType.STDERR);
+    errPumper.start();
+    
+    StreamPumper outPumper = new StreamPumper(
+        LOG, logPrefix, p.getInputStream(),
+        StreamPumper.StreamType.STDOUT);
+    outPumper.start();
+    
+    int rc;
+    try {
+      rc = p.waitFor();
+      errPumper.join();
+      outPumper.join();
+    } catch (InterruptedException ie) {
+      LOG.warn("Interrupted while waiting for fencing command: " + cmd);
+      return false;
+    }
+    
+    return rc == 0;
+  }
+
+  /**
+   * Abbreviate a string by putting '...' in the middle of it,
+   * in an attempt to keep logs from getting too messy.
+   * @param cmd the string to abbreviate
+   * @param len maximum length to abbreviate to
+   * @return abbreviated string
+   */
+  static String abbreviate(String cmd, int len) {
+    if (cmd.length() > len && len >= 5) {
+      int firstHalf = (len - 3) / 2;
+      int rem = len - firstHalf - 3;
+      
+      return cmd.substring(0, firstHalf) + 
+        "..." + cmd.substring(cmd.length() - rem);
+    } else {
+      return cmd;
+    }
+  }
+  
+  /**
+   * Attempt to use evil reflection tricks to determine the
+   * pid of a launched process. This is helpful to ops
+   * if debugging a fencing process that might have gone
+   * wrong. If running on a system or JVM where this doesn't
+   * work, it will simply return null.
+   */
+  private static String tryGetPid(Process p) {
+    try {
+      Class<? extends Process> clazz = p.getClass();
+      if (clazz.getName().equals("java.lang.UNIXProcess")) {
+        Field f = clazz.getDeclaredField("pid");
+        f.setAccessible(true);
+        return String.valueOf(f.getInt(p));
+      } else {
+        LOG.trace("Unable to determine pid for " + p
+            + " since it is not a UNIXProcess");
+        return null;
+      }
+    } catch (Throwable t) {
+      LOG.trace("Unable to determine pid for " + p, t);
+      return null;
+    }
+  }
+
+  /**
+   * Set the environment of the subprocess to be the Configuration,
+   * with '.'s replaced by '_'s.
+   */
+  private void setConfAsEnvVars(Map<String, String> env) {
+    for (Map.Entry<String, String> pair : getConf()) {
+      env.put(pair.getKey().replace('.', '_'), pair.getValue());
+    }
+  }
+}

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/SshFenceByTcpPort.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/SshFenceByTcpPort.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/SshFenceByTcpPort.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/SshFenceByTcpPort.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,352 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.Collection;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configured;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.jcraft.jsch.ChannelExec;
+import com.jcraft.jsch.JSch;
+import com.jcraft.jsch.JSchException;
+import com.jcraft.jsch.Session;
+
+/**
+ * This fencing implementation sshes to the target node and uses <code>fuser</code>
+ * to kill the process listening on the NameNode's TCP port. This is
+ * more accurate than using "jps" since it doesn't require parsing,
+ * and will work even if there are multiple NameNodes running on the
+ * same machine.<p>
+ * It returns a successful status code if:
+ * <ul>
+ * <li><code>fuser</code> indicates it successfully killed a process, <em>or</em>
+ * <li><code>nc -z</code> indicates that nothing is listening on the target port
+ * </ul>
+ * <p>
+ * This fencing mechanism is configured as following in the fencing method
+ * list:
+ * <code>sshfence([username@]nnhost[:ssh-port][, target-nn-port])</code>
+ * where the first argument specifies the username, host, and port to ssh
+ * into, and the second argument specifies the port on which the target
+ * NN process is listening on.
+ * <p>
+ * For example, <code>sshfence(other-nn, 8020)<code> will SSH into
+ * <code>other-nn<code> as the current user on the standard SSH port,
+ * then kill whatever process is listening on port 8020.
+ * <p>
+ * If no <code>target-nn-port</code> is specified, it is assumed that the
+ * target NameNode is listening on the same port as the local NameNode.
+ * <p>
+ * In order to achieve passwordless SSH, the operator must also configure
+ * <code>dfs.namenode.ha.fencing.ssh.private-key-files<code> to point to an
+ * SSH key that has passphrase-less access to the given username and host.
+ */
+public class SshFenceByTcpPort extends Configured
+  implements FenceMethod {
+
+  static final Log LOG = LogFactory.getLog(
+      SshFenceByTcpPort.class);
+  
+  static final String CONF_CONNECT_TIMEOUT_KEY =
+    "dfs.namenode.ha.fencing.ssh.connect-timeout";
+  private static final int CONF_CONNECT_TIMEOUT_DEFAULT =
+    30*1000;
+  static final String CONF_IDENTITIES_KEY =
+    "dfs.namenode.ha.fencing.ssh.private-key-files";
+
+  /**
+   * Verify that the arguments are parseable and that the host
+   * can be resolved.
+   */
+  @Override
+  public void checkArgs(String argStr) throws BadFencingConfigurationException {
+    Args args = new Args(argStr);
+    try {
+      InetAddress.getByName(args.host);
+    } catch (UnknownHostException e) {
+      throw new BadFencingConfigurationException(
+          "Unknown host: " + args.host);
+    }
+  }
+
+  @Override
+  public boolean tryFence(String argsStr)
+      throws BadFencingConfigurationException {
+    Args args = new Args(argsStr);
+    
+    Session session;
+    try {
+      session = createSession(args);
+    } catch (JSchException e) {
+      LOG.warn("Unable to create SSH session", e);
+      return false;
+    }
+
+    LOG.info("Connecting to " + args.host + "...");
+    
+    try {
+      session.connect(getSshConnectTimeout());
+    } catch (JSchException e) {
+      LOG.warn("Unable to connect to " + args.host
+          + " as user " + args.user, e);
+      return false;
+    }
+    LOG.info("Connected to " + args.host);
+
+    int targetPort = args.targetPort != null ?
+        args.targetPort : getDefaultNNPort();
+    try {
+      return doFence(session, targetPort);
+    } catch (JSchException e) {
+      LOG.warn("Unable to achieve fencing on remote host", e);
+      return false;
+    } finally {
+      session.disconnect();
+    }
+  }
+
+
+  private Session createSession(Args args) throws JSchException {
+    JSch jsch = new JSch();
+    for (String keyFile : getKeyFiles()) {
+      jsch.addIdentity(keyFile);
+    }
+    JSch.setLogger(new LogAdapter());
+
+    Session session = jsch.getSession(args.user, args.host, args.sshPort);
+    session.setConfig("StrictHostKeyChecking", "no");
+    return session;
+  }
+
+  private boolean doFence(Session session, int nnPort) throws JSchException {
+    try {
+      LOG.info("Looking for process running on port " + nnPort);
+      int rc = execCommand(session,
+          "PATH=$PATH:/sbin:/usr/sbin fuser -v -k -n tcp " + nnPort);
+      if (rc == 0) {
+        LOG.info("Successfully killed process that was " +
+            "listening on port " + nnPort);
+        // exit code 0 indicates the process was successfully killed.
+        return true;
+      } else if (rc == 1) {
+        // exit code 1 indicates either that the process was not running
+        // or that fuser didn't have root privileges in order to find it
+        // (eg running as a different user)
+        LOG.info(
+            "Indeterminate response from trying to kill NameNode. " +
+            "Verifying whether it is running using nc...");
+        rc = execCommand(session, "nc -z localhost 8020");
+        if (rc == 0) {
+          // the NN is still listening - we are unable to fence
+          LOG.warn("Unable to fence NN - it is running but we cannot kill it");
+          return false;
+        } else {
+          LOG.info("Verified that the NN is down.");
+          return true;          
+        }
+      } else {
+        // other 
+      }
+      LOG.info("rc: " + rc);
+      return rc == 0;
+    } catch (InterruptedException e) {
+      LOG.warn("Interrupted while trying to fence via ssh", e);
+      return false;
+    } catch (IOException e) {
+      LOG.warn("Unknown failure while trying to fence via ssh", e);
+      return false;
+    }
+  }
+  
+  /**
+   * Execute a command through the ssh session, pumping its
+   * stderr and stdout to our own logs.
+   */
+  private int execCommand(Session session, String cmd)
+      throws JSchException, InterruptedException, IOException {
+    LOG.debug("Running cmd: " + cmd);
+    ChannelExec exec = null;
+    try {
+      exec = (ChannelExec)session.openChannel("exec");
+      exec.setCommand(cmd);
+      exec.setInputStream(null);
+      exec.connect();
+      
+
+      // Pump stdout of the command to our WARN logs
+      StreamPumper outPumper = new StreamPumper(LOG, cmd + " via ssh",
+          exec.getInputStream(), StreamPumper.StreamType.STDOUT);
+      outPumper.start();
+      
+      // Pump stderr of the command to our WARN logs
+      StreamPumper errPumper = new StreamPumper(LOG, cmd + " via ssh",
+          exec.getErrStream(), StreamPumper.StreamType.STDERR);
+      errPumper.start();
+      
+      outPumper.join();
+      errPumper.join();
+      return exec.getExitStatus();
+    } finally {
+      cleanup(exec);
+    }
+  }
+
+  private static void cleanup(ChannelExec exec) {
+    if (exec != null) {
+      try {
+        exec.disconnect();
+      } catch (Throwable t) {
+        LOG.warn("Couldn't disconnect ssh channel", t);
+      }
+    }
+  }
+
+  private int getSshConnectTimeout() {
+    return getConf().getInt(
+        CONF_CONNECT_TIMEOUT_KEY, CONF_CONNECT_TIMEOUT_DEFAULT);
+  }
+
+  private Collection<String> getKeyFiles() {
+    return getConf().getTrimmedStringCollection(CONF_IDENTITIES_KEY);
+  }
+  
+  private int getDefaultNNPort() {
+    return NameNode.getAddress(getConf()).getPort();
+  }
+
+  /**
+   * Container for the parsed arg line for this fencing method.
+   */
+  @VisibleForTesting
+  static class Args {
+    private static final Pattern USER_HOST_PORT_RE = Pattern.compile(
+      "(?:(.+?)@)?([^:]+?)(?:\\:(\\d+))?");
+
+    private static final int DEFAULT_SSH_PORT = 22;
+
+    final String user;
+    final String host;
+    final int sshPort;
+    
+    final Integer targetPort;
+    
+    public Args(String args) throws BadFencingConfigurationException {
+      if (args == null) {
+        throw new BadFencingConfigurationException(
+            "Must specify args for ssh fencing configuration");
+      }
+      String[] argList = args.split(",\\s*");
+      if (argList.length > 2 || argList.length == 0) {
+        throw new BadFencingConfigurationException(
+            "Incorrect number of arguments: " + args);
+      }
+      
+      // Parse SSH destination.
+      String sshDestArg = argList[0];
+      Matcher m = USER_HOST_PORT_RE.matcher(sshDestArg);
+      if (!m.matches()) {
+        throw new BadFencingConfigurationException(
+            "Unable to parse SSH destination: "+ sshDestArg);
+      }
+      if (m.group(1) != null) {
+        user = m.group(1);
+      } else {
+        user = System.getProperty("user.name");
+      }
+      
+      host = m.group(2);
+
+      if (m.group(3) != null) {
+        sshPort = parseConfiggedPort(m.group(3));
+      } else {
+        sshPort = DEFAULT_SSH_PORT;
+      }
+      
+      // Parse target port.
+      if (argList.length > 1) {
+        targetPort = parseConfiggedPort(argList[1]);
+      } else {
+        targetPort = null;
+      }
+    }
+
+    private Integer parseConfiggedPort(String portStr)
+        throws BadFencingConfigurationException {
+      try {
+        return Integer.valueOf(portStr);
+      } catch (NumberFormatException nfe) {
+        throw new BadFencingConfigurationException(
+            "Port number '" + portStr + "' invalid");
+      }
+    }
+  }
+
+  /**
+   * Adapter from JSch's logger interface to our log4j
+   */
+  private static class LogAdapter implements com.jcraft.jsch.Logger {
+    static final Log LOG = LogFactory.getLog(
+        SshFenceByTcpPort.class.getName() + ".jsch");
+
+    public boolean isEnabled(int level) {
+      switch (level) {
+      case com.jcraft.jsch.Logger.DEBUG:
+        return LOG.isDebugEnabled();
+      case com.jcraft.jsch.Logger.INFO:
+        return LOG.isInfoEnabled();
+      case com.jcraft.jsch.Logger.WARN:
+        return LOG.isWarnEnabled();
+      case com.jcraft.jsch.Logger.ERROR:
+        return LOG.isErrorEnabled();
+      case com.jcraft.jsch.Logger.FATAL:
+        return LOG.isFatalEnabled();
+      default:
+        return false;
+      }
+    }
+      
+    public void log(int level, String message) {
+      switch (level) {
+      case com.jcraft.jsch.Logger.DEBUG:
+        LOG.debug(message);
+        break;
+      case com.jcraft.jsch.Logger.INFO:
+        LOG.info(message);
+        break;
+      case com.jcraft.jsch.Logger.WARN:
+        LOG.warn(message);
+        break;
+      case com.jcraft.jsch.Logger.ERROR:
+        LOG.error(message);
+        break;
+      case com.jcraft.jsch.Logger.FATAL:
+        LOG.fatal(message);
+        break;
+      }
+    }
+  }
+}

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyState.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyState.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyState.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StandbyState.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,58 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import org.apache.hadoop.ha.ServiceFailedException;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+
+/**
+ * Namenode standby state. In this state the namenode acts as warm standby and
+ * keeps the following updated:
+ * <ul>
+ * <li>Namespace by getting the edits.</li>
+ * <li>Block location information by receiving block reports and blocks
+ * received from the datanodes.</li>
+ * </ul>
+ * 
+ * It does not handle read/write/checkpoint operations.
+ */
+public class StandbyState extends HAState {
+  public StandbyState() {
+    super("standby");
+  }
+
+  @Override
+  public void setState(NameNode nn, HAState s) throws ServiceFailedException {
+    if (s == NameNode.ACTIVE_STATE) {
+      setStateInternal(nn, s);
+      return;
+    }
+    super.setState(nn, s);
+  }
+
+  @Override
+  protected void enterState(NameNode nn) throws ServiceFailedException {
+    // TODO:HA
+  }
+
+  @Override
+  protected void exitState(NameNode nn) throws ServiceFailedException {
+    // TODO:HA
+  }
+}
+

Added: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StreamPumper.java
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StreamPumper.java?rev=1162279&view=auto
==============================================================================
--- hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StreamPumper.java (added)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/StreamPumper.java Fri Aug 26 22:46:17 2011
@@ -0,0 +1,90 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import java.io.BufferedReader;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.InputStreamReader;
+
+import org.apache.commons.logging.Log;
+
+/**
+ * Class responsible for pumping the streams of the subprocess
+ * out to log4j. stderr is pumped to WARN level and stdout is
+ * pumped to INFO level
+ */
+class StreamPumper {
+  enum StreamType {
+    STDOUT, STDERR;
+  }
+
+  private final Log log;
+  
+  final Thread thread;
+  final String logPrefix;
+  final StreamPumper.StreamType type;
+  private final InputStream stream;
+  private boolean started = false;
+  
+  StreamPumper(final Log log, final String logPrefix,
+      final InputStream stream, final StreamType type) {
+    this.log = log;
+    this.logPrefix = logPrefix;
+    this.stream = stream;
+    this.type = type;
+    
+    thread = new Thread(new Runnable() {
+      @Override
+      public void run() {
+        try {
+          pump();
+        } catch (Throwable t) {
+          ShellCommandFencer.LOG.warn(logPrefix +
+              ": Unable to pump output from " + type,
+              t);
+        }
+      }
+    }, logPrefix + ": StreamPumper for " + type);
+    thread.setDaemon(true);
+  }
+  
+  void join() throws InterruptedException {
+    assert started;
+    thread.join();
+  }
+
+  void start() {
+    assert !started;
+    thread.start();
+    started = true;
+  }
+
+  protected void pump() throws IOException {
+    InputStreamReader inputStreamReader = new InputStreamReader(stream);
+    BufferedReader br = new BufferedReader(inputStreamReader);
+    String line = null;
+    while ((line = br.readLine()) != null) {
+      if (type == StreamType.STDOUT) {
+        log.info(logPrefix + ": " + line);
+      } else {
+        log.warn(logPrefix + ": " + line);          
+      }
+    }
+  }
+}

Copied: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java (from r1162221, hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java)
URL: http://svn.apache.org/viewvc/hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java?p2=hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java&p1=hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java&r1=1162221&r2=1162279&rev=1162279&view=diff
==============================================================================
--- hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java (original)
+++ hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/protocol/NamenodeProtocols.java Fri Aug 26 22:46:17 2011
@@ -19,6 +19,7 @@
 package org.apache.hadoop.hdfs.server.protocol;
 
 import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.ha.HAServiceProtocol;
 import org.apache.hadoop.hdfs.protocol.ClientProtocol;
 import org.apache.hadoop.security.authorize.RefreshAuthorizationPolicyProtocol;
 import org.apache.hadoop.security.RefreshUserMappingsProtocol;
@@ -32,5 +33,6 @@ public interface NamenodeProtocols
           NamenodeProtocol,
           RefreshAuthorizationPolicyProtocol,
           RefreshUserMappingsProtocol,
-          GetUserMappingsProtocol {
+          GetUserMappingsProtocol,
+          HAServiceProtocol {
 }

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/native/
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--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,8 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/native:1152502-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/main/native:713112
+/hadoop/core/branches/branch-0.19/mapred/src/c++/libhdfs:713112
+/hadoop/core/trunk/src/c++/libhdfs:776175-784663
+/hadoop/hdfs/branches/HDFS-1052/src/c++/libhdfs:987665-1095512
+/hadoop/hdfs/branches/HDFS-1052/src/main/native:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/main/native:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/main/native:820487

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--- svn:mergeinfo (added)
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@@ -0,0 +1,10 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/datanode:1159757-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/main/webapps/datanode:713112
+/hadoop/core/branches/branch-0.19/hdfs/src/webapps/datanode:713112
+/hadoop/core/trunk/src/webapps/datanode:776175-784663
+/hadoop/hdfs/branches/HDFS-1052/src/main/webapps/datanode:987665-1095512
+/hadoop/hdfs/branches/HDFS-1052/src/webapps/datanode:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/main/webapps/datanode:796829-820463
+/hadoop/hdfs/branches/HDFS-265/src/webapps/datanode:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/main/webapps/datanode:820487
+/hadoop/hdfs/branches/branch-0.21/src/webapps/datanode:820487

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/
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--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,10 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs:1152502-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/main/webapps/hdfs:713112
+/hadoop/core/branches/branch-0.19/hdfs/src/webapps/hdfs:713112
+/hadoop/core/trunk/src/webapps/hdfs:776175-784663
+/hadoop/hdfs/branches/HDFS-1052/src/main/webapps/hdfs:987665-1095512
+/hadoop/hdfs/branches/HDFS-1052/src/webapps/hdfs:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/main/webapps/hdfs:796829-820463
+/hadoop/hdfs/branches/HDFS-265/src/webapps/hdfs:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/main/webapps/hdfs:820487
+/hadoop/hdfs/branches/branch-0.21/src/webapps/hdfs:820487

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/secondary/
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--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,10 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/secondary:1152502-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/main/webapps/secondary:713112
+/hadoop/core/branches/branch-0.19/hdfs/src/webapps/secondary:713112
+/hadoop/core/trunk/src/webapps/secondary:776175-784663
+/hadoop/hdfs/branches/HDFS-1052/src/main/webapps/secondary:987665-1095512
+/hadoop/hdfs/branches/HDFS-1052/src/webapps/secondary:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/main/webapps/secondary:796829-820463
+/hadoop/hdfs/branches/HDFS-265/src/webapps/secondary:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/main/webapps/secondary:820487
+/hadoop/hdfs/branches/branch-0.21/src/webapps/secondary:820487

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/test/
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--- svn:externals (added)
+++ svn:externals Fri Aug 26 22:46:17 2011
@@ -0,0 +1 @@
+bin https://svn.apache.org/repos/asf/hadoop/common/trunk/common/src/test/bin

Propchange: hadoop/common/branches/HDFS-1623/hadoop-hdfs-project/hadoop-hdfs/src/test/hdfs/
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--- svn:mergeinfo (added)
+++ svn:mergeinfo Fri Aug 26 22:46:17 2011
@@ -0,0 +1,6 @@
+/hadoop/common/trunk/hadoop-hdfs-project/hadoop-hdfs/src/test/hdfs:1159757-1162221
+/hadoop/core/branches/branch-0.19/hdfs/src/test/hdfs:713112
+/hadoop/core/trunk/src/test/hdfs:776175-785643
+/hadoop/hdfs/branches/HDFS-1052/src/test/hdfs:987665-1095512
+/hadoop/hdfs/branches/HDFS-265/src/test/hdfs:796829-820463
+/hadoop/hdfs/branches/branch-0.21/src/test/hdfs:820487