org.apache.hadoop.hdfs.server.protocol

接口 DatanodeProtocol

所有超级接口:

VersionedProtocol

所有已知实现类:

NameNode

public interface DatanodeProtocol
extends VersionedProtocol

Protocol that a DFS datanode uses to communicate with the NameNode. It's used to upload current load information and block reports. The only way a NameNode can communicate with a DataNode is by returning values from these functions.

字段概要

字段

限定符和类型	字段和说明
static int	DISK_ERROR
static int	DNA_ACCESSKEYUPDATE
static int	DNA_BALANCERBANDWIDTHUPDATE
static int	DNA_FINALIZE
static int	DNA_INVALIDATE
static int	DNA_RECOVERBLOCK
static int	DNA_REGISTER
static int	DNA_SHUTDOWN
static int	DNA_TRANSFER
static int	DNA_UNKNOWN Determines actions that data node should perform when receiving a datanode command.
static int	FATAL_DISK_ERROR
static int	INVALID_BLOCK
static int	NOTIFY
static long	versionID 26: Added an additional member to NamespaceInfo

方法概要

方法

限定符和类型	方法和说明
void	blockReceived(DatanodeRegistration registration, Block[] blocks, String[] delHints) blockReceived() allows the DataNode to tell the NameNode about recently-received block data, with a hint for pereferred replica to be deleted when there is any excessive blocks.
DatanodeCommand	blockReport(DatanodeRegistration registration, long[] blocks) blockReport() tells the NameNode about all the locally-stored blocks.
void	blocksBeingWrittenReport(DatanodeRegistration registration, long[] blocks) blocksBeingWrittenReport() tells the NameNode about the blocks-being- written information
void	commitBlockSynchronization(Block block, long newgenerationstamp, long newlength, boolean closeFile, boolean deleteblock, DatanodeID[] newtargets) Commit block synchronization in lease recovery
void	errorReport(DatanodeRegistration registration, int errorCode, String msg) errorReport() tells the NameNode about something that has gone awry.
long	nextGenerationStamp(Block block, boolean fromNN) Get the next GenerationStamp to be associated with the specified block.
UpgradeCommand	processUpgradeCommand(UpgradeCommand comm) This is a very general way to send a command to the name-node during distributed upgrade process.
DatanodeRegistration	register(DatanodeRegistration registration) Register Datanode.
void	reportBadBlocks(LocatedBlock[] blocks) same as ClientProtocol.reportBadBlocks(LocatedBlock[]) }
DatanodeCommand[]	sendHeartbeat(DatanodeRegistration registration, long capacity, long dfsUsed, long remaining, int xmitsInProgress, int xceiverCount) sendHeartbeat() tells the NameNode that the DataNode is still alive and well.
NamespaceInfo	versionRequest()

从接口继承的方法 org.apache.hadoop.ipc.VersionedProtocol

getProtocolVersion

字段详细资料

versionID

static final long versionID

26: Added an additional member to NamespaceInfo

另请参阅:

常量字段值

NOTIFY

static final int NOTIFY

另请参阅:

常量字段值

DISK_ERROR

static final int DISK_ERROR

另请参阅:

常量字段值

INVALID_BLOCK

static final int INVALID_BLOCK

另请参阅:

常量字段值

FATAL_DISK_ERROR

static final int FATAL_DISK_ERROR

另请参阅:

常量字段值

DNA_UNKNOWN

static final int DNA_UNKNOWN

Determines actions that data node should perform when receiving a datanode command.

另请参阅:

常量字段值

DNA_TRANSFER

static final int DNA_TRANSFER

另请参阅:

常量字段值

DNA_INVALIDATE

static final int DNA_INVALIDATE

另请参阅:

常量字段值

DNA_SHUTDOWN

static final int DNA_SHUTDOWN

另请参阅:

常量字段值

DNA_REGISTER

static final int DNA_REGISTER

另请参阅:

常量字段值

DNA_FINALIZE

static final int DNA_FINALIZE

另请参阅:

常量字段值

DNA_RECOVERBLOCK

static final int DNA_RECOVERBLOCK

另请参阅:

常量字段值

DNA_ACCESSKEYUPDATE

static final int DNA_ACCESSKEYUPDATE

另请参阅:

常量字段值

DNA_BALANCERBANDWIDTHUPDATE

static final int DNA_BALANCERBANDWIDTHUPDATE

另请参阅:

常量字段值

方法详细资料

register

DatanodeRegistration register(DatanodeRegistration registration)
                              throws IOException

Register Datanode.

返回:

updated DatanodeRegistration, which contains new storageID if the datanode did not have one and registration ID for further communication.

抛出:

IOException

另请参阅:

DataNode.dnRegistration, FSNamesystem.registerDatanode(DatanodeRegistration)

sendHeartbeat

DatanodeCommand[] sendHeartbeat(DatanodeRegistration registration,
                              long capacity,
                              long dfsUsed,
                              long remaining,
                              int xmitsInProgress,
                              int xceiverCount)
                                throws IOException

sendHeartbeat() tells the NameNode that the DataNode is still alive and well. Includes some status info, too. It also gives the NameNode a chance to return an array of "DatanodeCommand" objects. A DatanodeCommand tells the DataNode to invalidate local block(s), or to copy them to other DataNodes, etc.

抛出:

IOException

blockReport

DatanodeCommand blockReport(DatanodeRegistration registration,
                          long[] blocks)
                            throws IOException

blockReport() tells the NameNode about all the locally-stored blocks. The NameNode returns an array of Blocks that have become obsolete and should be deleted. This function is meant to upload *all* the locally-stored blocks. It's invoked upon startup and then infrequently afterwards.

参数:

registration -

blocks - - the block list as an array of longs. Each block is represented as 2 longs. This is done instead of Block[] to reduce memory used by block reports.

返回:

- the next command for DN to process.

抛出:

IOException

blocksBeingWrittenReport

void blocksBeingWrittenReport(DatanodeRegistration registration,
                            long[] blocks)
                              throws IOException

blocksBeingWrittenReport() tells the NameNode about the blocks-being- written information

参数:

registration -

blocks -

抛出:

IOException

blockReceived

void blockReceived(DatanodeRegistration registration,
                 Block[] blocks,
                 String[] delHints)
                   throws IOException

blockReceived() allows the DataNode to tell the NameNode about recently-received block data, with a hint for pereferred replica to be deleted when there is any excessive blocks. For example, whenever client code writes a new Block here, or another DataNode copies a Block to this DataNode, it will call blockReceived().

抛出:

IOException

errorReport

void errorReport(DatanodeRegistration registration,
               int errorCode,
               String msg)
                 throws IOException

errorReport() tells the NameNode about something that has gone awry. Useful for debugging.

抛出:

IOException

versionRequest

NamespaceInfo versionRequest()
                             throws IOException

抛出:

IOException

processUpgradeCommand

UpgradeCommand processUpgradeCommand(UpgradeCommand comm)
                                     throws IOException

This is a very general way to send a command to the name-node during distributed upgrade process. The generosity is because the variety of upgrade commands is unpredictable. The reply from the name-node is also received in the form of an upgrade command.

返回:

a reply in the form of an upgrade command

抛出:

IOException

reportBadBlocks

void reportBadBlocks(LocatedBlock[] blocks)
                     throws IOException

same as ClientProtocol.reportBadBlocks(LocatedBlock[]) }

抛出:

IOException

nextGenerationStamp

long nextGenerationStamp(Block block,
                       boolean fromNN)
                         throws IOException

Get the next GenerationStamp to be associated with the specified block.

参数:

block - block

fromNN - if it is for lease recovery initiated by NameNode

返回:

a new generation stamp

抛出:

IOException

commitBlockSynchronization

void commitBlockSynchronization(Block block,
                              long newgenerationstamp,
                              long newlength,
                              boolean closeFile,
                              boolean deleteblock,
                              DatanodeID[] newtargets)
                                throws IOException

Commit block synchronization in lease recovery

抛出:

IOException