/**
* 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.dfs;
import org.apache.commons.logging.*;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.io.*;
import org.apache.hadoop.ipc.*;
import org.apache.hadoop.conf.*;
import org.apache.hadoop.util.StringUtils;
import java.io.*;
import org.apache.hadoop.metrics.MetricsRecord;
import org.apache.hadoop.metrics.Metrics;
/**********************************************************
* NameNode serves as both directory namespace manager and
* "inode table" for the Hadoop DFS. There is a single NameNode
* running in any DFS deployment. (Well, except when there
* is a second backup/failover NameNode.)
*
* The NameNode controls two critical tables:
* 1) filename->blocksequence (namespace)
* 2) block->machinelist ("inodes")
*
* The first table is stored on disk and is very precious.
* The second table is rebuilt every time the NameNode comes
* up.
*
* 'NameNode' refers to both this class as well as the 'NameNode server'.
* The 'FSNamesystem' class actually performs most of the filesystem
* management. The majority of the 'NameNode' class itself is concerned
* with exposing the IPC interface to the outside world, plus some
* configuration management.
*
* NameNode implements the ClientProtocol interface, which allows
* clients to ask for DFS services. ClientProtocol is not
* designed for direct use by authors of DFS client code. End-users
* should instead use the org.apache.nutch.hadoop.fs.FileSystem class.
*
* NameNode also implements the DatanodeProtocol interface, used by
* DataNode programs that actually store DFS data blocks. These
* methods are invoked repeatedly and automatically by all the
* DataNodes in a DFS deployment.
*
* @author Mike Cafarella
**********************************************************/
public class NameNode implements ClientProtocol, DatanodeProtocol, FSConstants {
public long getProtocolVersion(String protocol, long clientVersion) {
if (protocol.equals(ClientProtocol.class.getName())) {
return ClientProtocol.versionID;
} else {
return DatanodeProtocol.versionID;
}
}
public static final Log LOG = LogFactory.getLog("org.apache.hadoop.dfs.NameNode");
public static final Log stateChangeLog = LogFactory.getLog( "org.apache.hadoop.dfs.StateChange");
private FSNamesystem namesystem;
private Server server;
private int handlerCount = 2;
/** only used for testing purposes */
private boolean stopRequested = false;
/** Format a new filesystem. Destroys any filesystem that may already
* exist at this location. **/
public static void format(Configuration conf) throws IOException {
File[] dirs = getDirs(conf);
for (int idx = 0; idx < dirs.length; idx++) {
FSImage.format(dirs[idx]);
}
}
/** Format a new filesystem. Destroys any filesystem that may already
* exist at this location. **/
public static void format(File dir) throws IOException {
FSImage.format(dir);
}
private class NameNodeMetrics {
private MetricsRecord metricsRecord = null;
private long numFilesCreated = 0L;
private long numFilesOpened = 0L;
private long numFilesRenamed = 0L;
private long numFilesListed = 0L;
NameNodeMetrics() {
metricsRecord = Metrics.createRecord("dfs", "namenode");
}
synchronized void createFile() {
Metrics.report(metricsRecord, "files-created", ++numFilesCreated);
}
synchronized void openFile() {
Metrics.report(metricsRecord, "files-opened", ++numFilesOpened);
}
synchronized void renameFile() {
Metrics.report(metricsRecord, "files-renamed", ++numFilesRenamed);
}
synchronized void listFile(int nfiles) {
numFilesListed += nfiles;
Metrics.report(metricsRecord, "files-listed", numFilesListed);
}
}
private NameNodeMetrics myMetrics = null;
/**
* Create a NameNode at the default location
*/
public NameNode(Configuration conf) throws IOException {
this(getDirs(conf),DataNode.createSocketAddr(conf.get("fs.default.name", "local")).getHostName(),
DataNode.createSocketAddr(conf.get("fs.default.name", "local")).getPort(), conf);
}
/**
* Create a NameNode at the specified location and start it.
*/
public NameNode(File[] dirs, String bindAddress, int port, Configuration conf) throws IOException {
this.namesystem = new FSNamesystem(dirs, this, conf);
this.handlerCount = conf.getInt("dfs.namenode.handler.count", 10);
this.server = RPC.getServer(this, bindAddress, port, handlerCount, false, conf);
this.server.start();
myMetrics = new NameNodeMetrics();
}
/** Return the configured directories where name data is stored. */
private static File[] getDirs(Configuration conf) {
String[] dirNames = conf.getStrings("dfs.name.dir");
if (dirNames == null) { dirNames = new String[] {"/tmp/hadoop/dfs/name"}; }
File[] dirs = new File[dirNames.length];
for (int idx = 0; idx < dirs.length; idx++) {
dirs[idx] = new File(dirNames[idx]);
}
return dirs;
}
/**
* Wait for service to finish.
* (Normally, it runs forever.)
*/
public void join() {
try {
this.server.join();
} catch (InterruptedException ie) {
}
}
/**
* Stop all NameNode threads and wait for all to finish.
*/
public void stop() {
if (! stopRequested) {
stopRequested = true;
namesystem.close();
server.stop();
//this.join();
}
}
/////////////////////////////////////////////////////
// ClientProtocol
/////////////////////////////////////////////////////
/**
*/
public LocatedBlock[] open(String src) throws IOException {
Object openResults[] = namesystem.open(new UTF8(src));
if (openResults == null) {
throw new IOException("Cannot open filename " + src);
} else {
myMetrics.openFile();
Block blocks[] = (Block[]) openResults[0];
DatanodeInfo sets[][] = (DatanodeInfo[][]) openResults[1];
LocatedBlock results[] = new LocatedBlock[blocks.length];
for (int i = 0; i < blocks.length; i++) {
results[i] = new LocatedBlock(blocks[i], sets[i]);
}
return results;
}
}
/**
*/
public LocatedBlock create(String src,
String clientName,
String clientMachine,
boolean overwrite,
short replication,
long blockSize
) throws IOException {
stateChangeLog.debug("*DIR* NameNode.create: file "
+src+" for "+clientName+" at "+clientMachine);
if (!checkPathLength(src)) {
throw new IOException("create: Pathname too long. Limit "
+ MAX_PATH_LENGTH + " characters, " + MAX_PATH_DEPTH + " levels.");
}
Object results[] = namesystem.startFile(new UTF8(src),
new UTF8(clientName),
new UTF8(clientMachine),
overwrite,
replication,
blockSize);
myMetrics.createFile();
Block b = (Block) results[0];
DatanodeInfo targets[] = (DatanodeInfo[]) results[1];
return new LocatedBlock(b, targets);
}
public boolean setReplication( String src,
short replication
) throws IOException {
return namesystem.setReplication( src, replication );
}
/**
*/
public LocatedBlock addBlock(String src,
String clientName) throws IOException {
stateChangeLog.debug("*BLOCK* NameNode.addBlock: file "
+src+" for "+clientName);
UTF8 src8 = new UTF8(src);
UTF8 client8 = new UTF8(clientName);
Object[] results = namesystem.getAdditionalBlock(src8, client8);
Block b = (Block) results[0];
DatanodeInfo targets[] = (DatanodeInfo[]) results[1];
return new LocatedBlock(b, targets);
}
/**
* The client can report in a set written blocks that it wrote.
* These blocks are reported via the client instead of the datanode
* to prevent weird heartbeat race conditions.
*/
public void reportWrittenBlock(LocatedBlock lb) throws IOException {
Block b = lb.getBlock();
DatanodeInfo targets[] = lb.getLocations();
stateChangeLog.debug("*BLOCK* NameNode.reportWrittenBlock"
+": " + b.getBlockName() +" is written to "
+targets.length + " locations" );
for (int i = 0; i < targets.length; i++) {
namesystem.blockReceived( targets[i], b );
}
}
/**
* The client needs to give up on the block.
*/
public void abandonBlock(Block b, String src) throws IOException {
stateChangeLog.debug("*BLOCK* NameNode.abandonBlock: "
+b.getBlockName()+" of file "+src );
if (! namesystem.abandonBlock(b, new UTF8(src))) {
throw new IOException("Cannot abandon block during write to " + src);
}
}
/**
*/
public void abandonFileInProgress(String src,
String holder) throws IOException {
stateChangeLog.debug("*DIR* NameNode.abandonFileInProgress:" + src );
namesystem.abandonFileInProgress(new UTF8(src), new UTF8(holder));
}
/**
*/
public boolean complete(String src, String clientName) throws IOException {
stateChangeLog.debug("*DIR* NameNode.complete: " + src + " for " + clientName );
int returnCode = namesystem.completeFile(new UTF8(src), new UTF8(clientName));
if (returnCode == STILL_WAITING) {
return false;
} else if (returnCode == COMPLETE_SUCCESS) {
return true;
} else {
throw new IOException("Could not complete write to file " + src + " by " + clientName);
}
}
/**
*/
public String[][] getHints(String src, long start, long len) throws IOException {
return namesystem.getDatanodeHints( src, start, len );
}
public long getBlockSize(String filename) throws IOException {
return namesystem.getBlockSize(filename);
}
/**
*/
public boolean rename(String src, String dst) throws IOException {
stateChangeLog.debug("*DIR* NameNode.rename: " + src + " to " + dst );
if (!checkPathLength(dst)) {
throw new IOException("rename: Pathname too long. Limit "
+ MAX_PATH_LENGTH + " characters, " + MAX_PATH_DEPTH + " levels.");
}
boolean ret = namesystem.renameTo(new UTF8(src), new UTF8(dst));
if (ret) {
myMetrics.renameFile();
}
return ret;
}
/**
*/
public boolean delete(String src) throws IOException {
stateChangeLog.debug("*DIR* NameNode.delete: " + src );
return namesystem.delete(new UTF8(src));
}
/**
*/
public boolean exists(String src) throws IOException {
return namesystem.exists(new UTF8(src));
}
/**
*/
public boolean isDir(String src) throws IOException {
return namesystem.isDir(new UTF8(src));
}
/**
* Check path length does not exceed maximum. Returns true if
* length and depth are okay. Returns false if length is too long
* or depth is too great.
*
*/
private boolean checkPathLength(String src) {
Path srcPath = new Path(src);
return (src.length() <= MAX_PATH_LENGTH &&
srcPath.depth() <= MAX_PATH_DEPTH);
}
/**
*/
public boolean mkdirs(String src) throws IOException {
stateChangeLog.debug("*DIR* NameNode.mkdirs: " + src );
if (!checkPathLength(src)) {
throw new IOException("mkdirs: Pathname too long. Limit "
+ MAX_PATH_LENGTH + " characters, " + MAX_PATH_DEPTH + " levels.");
}
return namesystem.mkdirs( src );
}
/**
*/
public boolean obtainLock(String src, String clientName, boolean exclusive) throws IOException {
int returnCode = namesystem.obtainLock(new UTF8(src), new UTF8(clientName), exclusive);
if (returnCode == COMPLETE_SUCCESS) {
return true;
} else if (returnCode == STILL_WAITING) {
return false;
} else {
throw new IOException("Failure when trying to obtain lock on " + src);
}
}
/**
*/
public boolean releaseLock(String src, String clientName) throws IOException {
int returnCode = namesystem.releaseLock(new UTF8(src), new UTF8(clientName));
if (returnCode == COMPLETE_SUCCESS) {
return true;
} else if (returnCode == STILL_WAITING) {
return false;
} else {
throw new IOException("Failure when trying to release lock on " + src);
}
}
/**
*/
public void renewLease(String clientName) throws IOException {
namesystem.renewLease(new UTF8(clientName));
}
/**
*/
public DFSFileInfo[] getListing(String src) throws IOException {
DFSFileInfo[] files = namesystem.getListing(new UTF8(src));
if (files != null) {
myMetrics.listFile(files.length);
}
return files;
}
/**
*/
public long[] getStats() throws IOException {
long results[] = new long[2];
results[0] = namesystem.totalCapacity();
results[1] = namesystem.totalCapacity() - namesystem.totalRemaining();
return results;
}
/**
*/
public DatanodeInfo[] getDatanodeReport() throws IOException {
DatanodeInfo results[] = namesystem.datanodeReport();
if (results == null || results.length == 0) {
throw new IOException("Cannot find datanode report");
}
return results;
}
/**
* @inheritDoc
*/
public boolean setSafeMode( SafeModeAction action ) throws IOException {
switch( action ) {
case SAFEMODE_LEAVE: // leave safe mode
namesystem.leaveSafeMode();
break;
case SAFEMODE_ENTER: // enter safe mode
namesystem.enterSafeMode();
break;
case SAFEMODE_GET: // get safe mode
}
return namesystem.isInSafeMode();
}
/**
* Is the cluster currently in safe mode?
*/
boolean isInSafeMode() {
return namesystem.isInSafeMode();
}
////////////////////////////////////////////////////////////////
// DatanodeProtocol
////////////////////////////////////////////////////////////////
/**
*/
public DatanodeRegistration register( DatanodeRegistration nodeReg
) throws IOException {
verifyVersion( nodeReg.getVersion() );
namesystem.registerDatanode( nodeReg );
return nodeReg;
}
/**
* Data node notify the name node that it is alive
* Return a block-oriented command for the datanode to execute.
* This will be either a transfer or a delete operation.
*/
public BlockCommand sendHeartbeat(DatanodeRegistration nodeReg,
long capacity,
long remaining,
int xmitsInProgress,
int xceiverCount) throws IOException {
verifyRequest( nodeReg );
if( namesystem.gotHeartbeat( nodeReg, capacity, remaining, xceiverCount )) {
// request block report from the datanode
return new BlockCommand( DataNodeAction.DNA_REPORT );
}
//
// Ask to perform pending transfers, if any
//
Object xferResults[] = namesystem.pendingTransfers( nodeReg,
xmitsInProgress );
if (xferResults != null) {
return new BlockCommand((Block[]) xferResults[0], (DatanodeInfo[][]) xferResults[1]);
}
//
// If there are no transfers, check for recently-deleted blocks that
// should be removed. This is not a full-datanode sweep, as is done during
// a block report. This is just a small fast removal of blocks that have
// just been removed.
//
Block blocks[] = namesystem.blocksToInvalidate( nodeReg );
if (blocks != null) {
return new BlockCommand(blocks);
}
return null;
}
public Block[] blockReport( DatanodeRegistration nodeReg,
Block blocks[]) throws IOException {
verifyRequest( nodeReg );
stateChangeLog.debug("*BLOCK* NameNode.blockReport: "
+"from "+nodeReg.getName()+" "+blocks.length+" blocks" );
return namesystem.processReport( nodeReg, blocks );
}
public void blockReceived(DatanodeRegistration nodeReg,
Block blocks[]) throws IOException {
verifyRequest( nodeReg );
stateChangeLog.debug("*BLOCK* NameNode.blockReceived: "
+"from "+nodeReg.getName()+" "+blocks.length+" blocks." );
for (int i = 0; i < blocks.length; i++) {
namesystem.blockReceived( nodeReg, blocks[i] );
}
}
/**
*/
public void errorReport(DatanodeRegistration nodeReg,
int errorCode,
String msg) throws IOException {
// Log error message from datanode
verifyRequest( nodeReg );
LOG.warn("Report from " + nodeReg.getName() + ": " + msg);
if( errorCode == DatanodeProtocol.DISK_ERROR ) {
namesystem.removeDatanode( nodeReg );
}
}
/**
* Verify request.
*
* Verifies correctness of the datanode version and registration ID.
*
* @param nodeReg data node registration
* @throws IOException
*/
public void verifyRequest( DatanodeRegistration nodeReg ) throws IOException {
verifyVersion( nodeReg.getVersion() );
if( ! namesystem.getRegistrationID().equals( nodeReg.getRegistrationID() ))
throw new UnregisteredDatanodeException( nodeReg );
}
/**
* Verify version.
*
* @param version
* @throws IOException
*/
public void verifyVersion( int version ) throws IOException {
if( version != DFS_CURRENT_VERSION )
throw new IncorrectVersionException( version, "data node" );
}
/**
*/
public static void main(String argv[]) throws Exception {
try {
Configuration conf = new Configuration();
if (argv.length == 1 && argv[0].equals("-format")) {
boolean aborted = false;
File[] dirs = getDirs(conf);
for (int idx = 0; idx < dirs.length; idx++) {
if (dirs[idx].exists()) {
System.err.print("Re-format filesystem in " + dirs[idx] +" ? (Y or N) ");
if (!(System.in.read() == 'Y')) {
System.err.println("Format aborted in "+ dirs[idx]);
aborted = true;
} else {
format(dirs[idx]);
System.err.println("Formatted "+dirs[idx]);
}
System.in.read(); // discard the enter-key
}
}
System.exit(aborted ? 1 : 0);
}
NameNode namenode = new NameNode(conf);
namenode.join();
} catch ( Throwable e ) {
LOG.error( StringUtils.stringifyException( e ) );
System.exit(-1);
}
}
}