org.apache.hadoop.hdfs.server.blockmanagement

Class HostFileManager

java.lang.Object

org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

org.apache.hadoop.hdfs.server.blockmanagement.HostFileManager

All Implemented Interfaces:

org.apache.hadoop.conf.Configurable

public class HostFileManager
extends org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

This class manages the include and exclude files for HDFS.

These files control which DataNodes the NameNode expects to see in the cluster. Loosely speaking, the include file, if it exists and is not empty, is a list of everything we expect to see. The exclude file is a list of everything we want to ignore if we do see it.

Entries may or may not specify a port. If they don't, we consider them to apply to every DataNode on that host. The code canonicalizes the entries into IP addresses.

The code ignores all entries that the DNS fails to resolve their IP addresses. This is okay because by default the NN rejects the registrations of DNs when it fails to do a forward and reverse lookup. Note that DNS resolutions are only done during the loading time to minimize the latency.

Constructor Summary

Constructors

Constructor and Description
HostFileManager()

Method Summary

Methods

Modifier and Type	Method and Description
org.apache.hadoop.conf.Configuration	getConf()
HostSet	getExcludes() Return all datanodes that should be in decommissioned state.
HostSet	getIncludes() Return all the datanodes that are allowed to connect to the namenode.
String	getUpgradeDomain(org.apache.hadoop.hdfs.protocol.DatanodeID dn) Get the upgrade domain of a datanode.
boolean	isExcluded(org.apache.hadoop.hdfs.protocol.DatanodeID dn) Check if a datanode needs to be decommissioned.
boolean	isIncluded(org.apache.hadoop.hdfs.protocol.DatanodeID dn) Check if a datanode is allowed to connect the namenode.
void	refresh() Reload the configuration.
void	setConf(org.apache.hadoop.conf.Configuration conf)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

HostFileManager

public HostFileManager()

Method Detail

setConf

public void setConf(org.apache.hadoop.conf.Configuration conf)

getConf

public org.apache.hadoop.conf.Configuration getConf()

refresh

public void refresh()
             throws IOException

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Reload the configuration.

Specified by:

refresh in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Throws:

IOException

getIncludes

public HostSet getIncludes()

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Return all the datanodes that are allowed to connect to the namenode.

Specified by:

getIncludes in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Returns:

Iterable of all datanodes

getExcludes

public HostSet getExcludes()

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Return all datanodes that should be in decommissioned state.

Specified by:

getExcludes in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Returns:

Iterable of those datanodes

isIncluded

public boolean isIncluded(org.apache.hadoop.hdfs.protocol.DatanodeID dn)

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Check if a datanode is allowed to connect the namenode.

Specified by:

isIncluded in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Parameters:

dn - the DatanodeID of the datanode

Returns:

boolean if dn is allowed to connect the namenode.

isExcluded

public boolean isExcluded(org.apache.hadoop.hdfs.protocol.DatanodeID dn)

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Check if a datanode needs to be decommissioned.

Specified by:

isExcluded in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Parameters:

dn - the DatanodeID of the datanode

Returns:

boolean if dn needs to be decommissioned.

getUpgradeDomain

public String getUpgradeDomain(org.apache.hadoop.hdfs.protocol.DatanodeID dn)

Description copied from class: org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Get the upgrade domain of a datanode.

Specified by:

getUpgradeDomain in class org.apache.hadoop.hdfs.server.blockmanagement.HostConfigManager

Parameters:

dn - the DatanodeID of the datanode

Returns:

the upgrade domain of dn.