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

接口概要

接口	说明
FSClusterStats	This interface is used for retrieving the load related statistics of the cluster.
FSInodeInfo	This interface is used used the pluggable block placement policy to expose a few characteristics of an Inode.
NameNodeMXBean	This is the JMX management interface for namenode information

类概要

类	说明
BlockPlacementPolicy	This interface is used for choosing the desired number of targets for placing block replicas.
BlockPlacementPolicyDefault	The class is responsible for choosing the desired number of targets for placing block replicas.
BlockPlacementPolicyWithNodeGroup	The class is responsible for choosing the desired number of targets for placing block replicas on environment with node-group layer.
CancelDelegationTokenServlet	Cancel delegation tokens over http for use in hftp.
CheckpointSignature	A unique signature intended to identify checkpoint transactions.
ContentSummaryServlet	Servlets for file checksum
CorruptReplicasMap	Stores information about all corrupt blocks in the File System.
DatanodeDescriptor	DatanodeDescriptor tracks stats on a given DataNode, such as available storage capacity, last update time, etc., and maintains a set of blocks stored on the datanode.
DatanodeDescriptor.BlockTargetPair	Block and targets pair
FileChecksumServlets	Servlets for file checksum
FileChecksumServlets.GetServlet	Get FileChecksum
FileChecksumServlets.RedirectServlet	Redirect file checksum queries to an appropriate datanode.
FileDataServlet	Redirect queries about the hosted filesystem to an appropriate datanode.
FsckServlet	This class is used in Namesystem's web server to do fsck on namenode.
FSEditLog	FSEditLog maintains a log of the namespace modifications.
FSImage	FSImage handles checkpointing and logging of the namespace edits.
FSNamesystem	FSNamesystem does the actual bookkeeping work for the DataNode.
GetDelegationTokenServlet	Serve delegation tokens over http for use in hftp.
GetImageServlet	This class is used in Namesystem's jetty to retrieve a file.
JspHelper
LeaseManager	LeaseManager does the lease housekeeping for writing on files.
ListPathsServlet	Obtain meta-information about a filesystem.
MetaRecoveryContext	Context data for an ongoing NameNode recovery process.
NameNode	NameNode serves as both directory namespace manager and "inode table" for the Hadoop DFS.
NamenodeFsck	This class provides rudimentary checking of DFS volumes for errors and sub-optimal conditions.
RenewDelegationTokenServlet	Renew delegation tokens over http for use in hftp.
SecondaryNameNode	The Secondary NameNode is a helper to the primary NameNode.
StreamFile
UpgradeObjectNamenode	Base class for name-node upgrade objects.

异常错误概要

异常错误	说明
BlockPlacementPolicy.NotEnoughReplicasException
LeaseExpiredException	The lease that was being used to create this file has expired.
NotReplicatedYetException	The file has not finished being written to enough datanodes yet.
SafeModeException	This exception is thrown when the name node is in safe mode.
UnsupportedActionException	This exception is thrown when an operation is not supported.