Package org.apache.hadoop.hdfs.server.namenode

Class TransferFsImage

java.lang.Object

org.apache.hadoop.hdfs.server.namenode.TransferFsImage

@Private
public class TransferFsImage
extends Object

This class provides fetching a specified file from the NameNode.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	TransferFsImage.TransferResult

Constructor Summary

Constructors

Constructor	Description
TransferFsImage()

Method Summary

Modifier and Type	Method	Description
static void	copyFileToStream(OutputStream out, File localfile, FileInputStream infile, DataTransferThrottler throttler)	A server-side method to respond to a getfile http request Copies the contents of the local file into the output stream.
static org.apache.hadoop.io.MD5Hash	doGetUrl(URL url, List<File> localPaths, Storage dstStorage, boolean getChecksum)
static void	downloadAliasMap(URL fsName, File aliasMap, boolean isBootstrapStandby)	Download the InMemoryAliasMap from the remote NN.
static org.apache.hadoop.io.MD5Hash	downloadImageToStorage(URL fsName, long imageTxId, Storage dstStorage, boolean needDigest, boolean isBootstrapStandby)
static void	downloadMostRecentImageToDirectory(URL infoServer, File dir)
static TransferFsImage.TransferResult	uploadImageFromStorage(URL fsName, org.apache.hadoop.conf.Configuration conf, NNStorage storage, NNStorage.NameNodeFile nnf, long txid, Canceler canceler)	Requests that the NameNode download an image from this node.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

TransferFsImage

public TransferFsImage()

Method Details

downloadMostRecentImageToDirectory

public static void downloadMostRecentImageToDirectory(URL infoServer,
 File dir)
                                               throws IOException

Throws:

IOException

downloadImageToStorage

public static org.apache.hadoop.io.MD5Hash downloadImageToStorage(URL fsName,
 long imageTxId,
 Storage dstStorage,
 boolean needDigest,
 boolean isBootstrapStandby)
                                                           throws IOException

Throws:

IOException

downloadAliasMap

public static void downloadAliasMap(URL fsName,
 File aliasMap,
 boolean isBootstrapStandby)
                             throws IOException

Download the InMemoryAliasMap from the remote NN.

Parameters:

fsName - http address of remote NN.

aliasMap - location of the alias map.

isBootstrapStandby - flag to indicate if for bootstrap of standby.

Throws:

IOException

uploadImageFromStorage

public static TransferFsImage.TransferResult uploadImageFromStorage(URL fsName,
 org.apache.hadoop.conf.Configuration conf,
 NNStorage storage,
 NNStorage.NameNodeFile nnf,
 long txid,
 Canceler canceler)
                                                             throws IOException

Requests that the NameNode download an image from this node. Allows for optional external cancelation.

Parameters:

fsName - the http address for the remote NN

conf - Configuration

storage - the storage directory to transfer the image from

nnf - the NameNodeFile type of the image

txid - the transaction ID of the image to be uploaded

canceler - optional canceler to check for abort of upload

Throws:

IOException - if there is an I/O error or cancellation

copyFileToStream

public static void copyFileToStream(OutputStream out,
 File localfile,
 FileInputStream infile,
 DataTransferThrottler throttler)
                             throws IOException

A server-side method to respond to a getfile http request Copies the contents of the local file into the output stream.

Throws:

IOException

doGetUrl

public static org.apache.hadoop.io.MD5Hash doGetUrl(URL url,
 List<File> localPaths,
 Storage dstStorage,
 boolean getChecksum)
                                             throws IOException

Throws:

IOException