org.apache.hadoop.dfs
Class DatanodeDescriptor

java.lang.Object
  org.apache.hadoop.dfs.DatanodeID
      org.apache.hadoop.dfs.DatanodeInfo
          org.apache.hadoop.dfs.DatanodeDescriptor

All Implemented Interfaces:

Comparable<DatanodeID>, Writable, WritableComparable<DatanodeID>, Node

public class DatanodeDescriptor
extends DatanodeInfo

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. This data structure is a data structure that is internal to the namenode. It is *not* sent over-the-wire to the Client or the Datnodes. Neither is it stored persistently in the fsImage.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.hadoop.dfs.DatanodeInfo

DatanodeInfo.AdminStates

Field Summary

protected boolean

isAlive

Fields inherited from class org.apache.hadoop.dfs.DatanodeInfo

adminState, capacity, dfsUsed, hostName, lastUpdate, location, remaining, xceiverCount

Fields inherited from class org.apache.hadoop.dfs.DatanodeID

infoPort, ipcPort, name, storageID

Constructor Summary

DatanodeDescriptor()
Default constructor

DatanodeDescriptor(DatanodeID nodeID)
DatanodeDescriptor constructor

DatanodeDescriptor(DatanodeID nodeID, long capacity, long dfsUsed, long remaining, int xceiverCount)
DatanodeDescriptor constructor

DatanodeDescriptor(DatanodeID nodeID, String networkLocation)
DatanodeDescriptor constructor

DatanodeDescriptor(DatanodeID nodeID, String networkLocation, String hostName)
DatanodeDescriptor constructor

DatanodeDescriptor(DatanodeID nodeID, String networkLocation, String hostName, long capacity, long dfsUsed, long remaining, int xceiverCount)
DatanodeDescriptor constructor

Method Summary

int	getBlocksScheduled()

Methods inherited from class org.apache.hadoop.dfs.DatanodeInfo

getCapacity, getDatanodeReport, getDfsUsed, getHostName, getLastUpdate, getLevel, getNetworkLocation, getParent, getRemaining, getXceiverCount, readFields, setHostName, setLevel, setNetworkLocation, setParent, write

Methods inherited from class org.apache.hadoop.dfs.DatanodeID

compareTo, equals, getHost, getInfoPort, getIpcPort, getName, getPort, getStorageID, hashCode, toString

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Methods inherited from interface org.apache.hadoop.net.Node

getName

Field Detail

isAlive

protected boolean isAlive

Constructor Detail

DatanodeDescriptor

public DatanodeDescriptor()

Default constructor

DatanodeDescriptor

public DatanodeDescriptor(DatanodeID nodeID)

DatanodeDescriptor constructor

Parameters:

nodeID - id of the data node

DatanodeDescriptor

public DatanodeDescriptor(DatanodeID nodeID,
                          String networkLocation)

DatanodeDescriptor constructor

Parameters:

nodeID - id of the data node

networkLocation - location of the data node in network

DatanodeDescriptor

public DatanodeDescriptor(DatanodeID nodeID,
                          String networkLocation,
                          String hostName)

DatanodeDescriptor constructor

Parameters:

nodeID - id of the data node

networkLocation - location of the data node in network

hostName - it could be different from host specified for DatanodeID

DatanodeDescriptor

public DatanodeDescriptor(DatanodeID nodeID,
                          long capacity,
                          long dfsUsed,
                          long remaining,
                          int xceiverCount)

DatanodeDescriptor constructor

Parameters:

nodeID - id of the data node

capacity - capacity of the data node

dfsUsed - space used by the data node

remaining - remaing capacity of the data node

xceiverCount - # of data transfers at the data node

DatanodeDescriptor

public DatanodeDescriptor(DatanodeID nodeID,
                          String networkLocation,
                          String hostName,
                          long capacity,
                          long dfsUsed,
                          long remaining,
                          int xceiverCount)

DatanodeDescriptor constructor

Parameters:

nodeID - id of the data node

networkLocation - location of the data node in network

capacity - capacity of the data node, including space used by non-dfs

dfsUsed - the used space by dfs datanode

remaining - remaing capacity of the data node

xceiverCount - # of data transfers at the data node

Method Detail

getBlocksScheduled

public int getBlocksScheduled()

Returns:

Approximate number of blocks currently scheduled to be written to this datanode.