程序包 org.apache.hadoop.hdfs.server.protocol

接口概要

接口	说明
DatanodeProtocol	Protocol that a DFS datanode uses to communicate with the NameNode.
InterDatanodeProtocol	An inter-datanode protocol for updating generation stamp
NamenodeProtocol	Protocol that a secondary NameNode uses to communicate with the NameNode.

类概要

类	说明
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.
BlockMetaDataInfo	Meta data information for a block
BlockRecoveryInfo
BlocksWithLocations	A class to implement an array of BlockLocations It provide efficient customized serialization/deserialization methods in stead of using the default array (de)serialization provided by RPC
BlocksWithLocations.BlockWithLocations	A class to keep track of a block and its locations
DatanodeCommand
DatanodeRegistration	DatanodeRegistration class conatins all information the Namenode needs to identify and verify a Datanode when it contacts the Namenode.
KeyUpdateCommand
NamespaceInfo	NamespaceInfo is returned by the name-node in reply to a data-node handshake.
UpgradeCommand	This as a generic distributed upgrade command.

异常错误概要

异常错误	说明
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.