@LimitedPrivate("HDFS") @Evolving

Package org.apache.hadoop.hdfs.server.protocol

Interface Summary

Interface	Description
BalancerProtocols	The full set of protocols used by the Balancer.
DatanodeLifelineProtocol	Protocol used by a DataNode to send lifeline messages to a NameNode.
DatanodeProtocol	Protocol that a DFS datanode uses to communicate with the NameNode.
InterDatanodeProtocol	An inter-datanode protocol for updating generation stamp
JournalProtocol	Protocol used to journal edits to a remote node.
NamenodeProtocol	Protocol that a secondary NameNode uses to communicate with the NameNode.
NamenodeProtocols	The full set of RPC methods implemented by the Namenode.
NodeRegistration	Generic class specifying information, which need to be sent to the name-node during the registration process.

Class Summary

Class	Description
BalancerBandwidthCommand	Balancer bandwidth command instructs each datanode to change its value for the max amount of network bandwidth it may use during the block balancing operation.
BlockCommand	A BlockCommand is an instruction to a datanode regarding some blocks under its control.
BlockECReconstructionCommand	A BlockECReconstructionCommand is an instruction to a DataNode to reconstruct a striped block group with missing blocks.
BlockECReconstructionCommand.BlockECReconstructionInfo	Block and targets pair
BlockIdCommand	A BlockIdCommand is an instruction to a datanode regarding some blocks under its control.
BlockRecoveryCommand	BlockRecoveryCommand is an instruction to a data-node to recover the specified blocks.
BlockRecoveryCommand.RecoveringBlock	This is a block with locations from which it should be recovered and the new generation stamp, which the block will have after successful recovery.
BlockRecoveryCommand.RecoveringStripedBlock
BlockReportContext	The context of the block report.
BlocksStorageMoveAttemptFinished	This class represents, the blocks for which storage movements has done by datanodes.
BlockStorageMovementCommand	A BlockStorageMovementCommand is an instruction to a DataNode to move the given set of blocks to specified target DataNodes to fulfill the block storage policy.
BlockStorageMovementCommand.BlockMovingInfo	Stores block to storage info that can be used for block movement.
BlocksWithLocations	Maintains an array of blocks and their corresponding storage IDs.
BlocksWithLocations.BlockWithLocations	A class to keep track of a block and its locations
BlocksWithLocations.StripedBlockWithLocations
CheckpointCommand	Checkpoint command.
DatanodeCommand	Base class for data-node command.
DatanodeRegistration	DatanodeRegistration class contains all information the name-node needs to identify and verify a data-node when it contacts the name-node.
DropSPSWorkCommand	A DropSPSWorkCommand is an instruction to a datanode to drop the SPSWorker's pending block storage movement queues.
FenceResponse	Response to a journal fence request.
FinalizeCommand	A BlockCommand is an instruction to a datanode to register with the namenode.
HeartbeatResponse
JournalInfo	Information that describes a journal
KeyUpdateCommand
NamenodeCommand	Base class for name-node command.
NamenodeRegistration	Information sent by a subordinate name-node to the active name-node during the registration process.
NamespaceInfo	NamespaceInfo is returned by the name-node in reply to a data-node handshake.
NNHAStatusHeartbeat
ReceivedDeletedBlockInfo	A data structure to store the blocks in an incremental block report.
RegisterCommand	A RegisterCommand is an instruction to a datanode to register with the namenode.
RemoteEditLog
RemoteEditLogManifest	An enumeration of logs available on a remote NameNode.
ReplicaRecoveryInfo	Replica recovery information.
ServerCommand	Base class for a server command.
StorageBlockReport	Block report for a Datanode storage
StorageReceivedDeletedBlocks	Report of block received and deleted per Datanode storage.
VolumeFailureSummary	Summarizes information about data volume failures on a DataNode.

Enum Summary

Enum	Description
NamespaceInfo.Capability
ReceivedDeletedBlockInfo.BlockStatus

Exception Summary

Exception	Description
DisallowedDatanodeException	This exception is thrown when a datanode tries to register or communicate with the namenode when it does not appear on the list of included nodes, or has been specifically excluded.
FencedException	If a previous user of a resource tries to use a shared resource, after fenced by another user, this exception is thrown.
InvalidBlockReportLeaseException	This exception is thrown when a datanode sends a full block report but it is rejected by the Namenode due to an invalid lease (expired or otherwise).