org.apache.hadoop.hbase.master.balancer

Class MaintenanceLoadBalancer

java.lang.Object

org.apache.hadoop.hbase.master.balancer.MaintenanceLoadBalancer

All Implemented Interfaces:

ConfigurationObserver, LoadBalancer, Stoppable

@InterfaceAudience.Private
public class MaintenanceLoadBalancer
extends Object
implements LoadBalancer

a balancer which is only used in maintenance mode.

Field Summary

Fields

Modifier and Type	Field and Description
private boolean	stopped

Fields inherited from interface org.apache.hadoop.hbase.master.LoadBalancer

BOGUS_SERVER_NAME, SYSTEM_TABLES_ON_MASTER, TABLES_ON_MASTER

Constructor Summary

Constructors

Constructor and Description
MaintenanceLoadBalancer()

Method Summary

Modifier and Type	Method and Description
private Map<ServerName,List<RegionInfo>>	assign(Collection<RegionInfo> regions, List<ServerName> servers)
List<RegionPlan>	balanceCluster(Map<TableName,Map<ServerName,List<RegionInfo>>> loadOfAllTable) Perform the major balance operation for cluster.
void	initialize() Initialize the load balancer.
boolean	isStopped() Returns True if Stoppable.stop(String) has been closed.
void	onConfigurationChange(org.apache.hadoop.conf.Configuration conf) This method would be called by the ConfigurationManager object when the Configuration object is reloaded from disk.
void	postMasterStartupInitialize() If balancer needs to do initialization after Master has started up, lets do that here.
ServerName	randomAssignment(RegionInfo regionInfo, List<ServerName> servers) Get a random region server from the list
void	regionOffline(RegionInfo regionInfo) Marks the region as offline at balancer.
void	regionOnline(RegionInfo regionInfo, ServerName sn) Marks the region as online at balancer.
Map<ServerName,List<RegionInfo>>	retainAssignment(Map<RegionInfo,ServerName> regions, List<ServerName> servers) Assign regions to the previously hosting region server nn * @return List of plans
Map<ServerName,List<RegionInfo>>	roundRobinAssignment(List<RegionInfo> regions, List<ServerName> servers) Perform a Round Robin assignment of regions.
void	setMasterServices(MasterServices masterServices) Set the master service.
void	stop(String why) Stop this service.
void	updateBalancerStatus(boolean status)
void	updateClusterMetrics(ClusterMetrics st) Set the current cluster status.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.master.LoadBalancer

isMasterCanHostUserRegions, isSystemTablesOnlyOnMaster, isTablesOnMaster, updateBalancerLoadInfo

Field Detail

stopped

private volatile boolean stopped

Constructor Detail

MaintenanceLoadBalancer

public MaintenanceLoadBalancer()

Method Detail

stop

public void stop(String why)

Description copied from interface: Stoppable

Stop this service. Implementers should favor logging errors over throwing RuntimeExceptions.

Specified by:

stop in interface Stoppable

Parameters:

why - Why we're stopping.

isStopped

public boolean isStopped()

Description copied from interface: Stoppable

Returns True if Stoppable.stop(String) has been closed.

Specified by:

isStopped in interface Stoppable

updateClusterMetrics

public void updateClusterMetrics(ClusterMetrics st)

Description copied from interface: LoadBalancer

Set the current cluster status. This allows a LoadBalancer to map host name to a server

Specified by:

updateClusterMetrics in interface LoadBalancer

setMasterServices

public void setMasterServices(MasterServices masterServices)

Description copied from interface: LoadBalancer

Set the master service. n

Specified by:

setMasterServices in interface LoadBalancer

balanceCluster

public List<RegionPlan> balanceCluster(Map<TableName,Map<ServerName,List<RegionInfo>>> loadOfAllTable)
                                throws IOException

Description copied from interface: LoadBalancer

Perform the major balance operation for cluster.

Specified by:

balanceCluster in interface LoadBalancer

Parameters:

loadOfAllTable - region load of servers for all table

Returns:

a list of regions to be moved, including source and destination, or null if cluster is already balanced

Throws:

IOException

assign

private Map<ServerName,List<RegionInfo>> assign(Collection<RegionInfo> regions,
                                                List<ServerName> servers)

roundRobinAssignment

public Map<ServerName,List<RegionInfo>> roundRobinAssignment(List<RegionInfo> regions,
                                                             List<ServerName> servers)

Description copied from interface: LoadBalancer

Perform a Round Robin assignment of regions. nn * @return Map of servername to regioninfos

Specified by:

roundRobinAssignment in interface LoadBalancer

retainAssignment

public Map<ServerName,List<RegionInfo>> retainAssignment(Map<RegionInfo,ServerName> regions,
                                                         List<ServerName> servers)

Description copied from interface: LoadBalancer

Assign regions to the previously hosting region server nn * @return List of plans

Specified by:

retainAssignment in interface LoadBalancer

randomAssignment

public ServerName randomAssignment(RegionInfo regionInfo,
                                   List<ServerName> servers)

Description copied from interface: LoadBalancer

Get a random region server from the list

Specified by:

randomAssignment in interface LoadBalancer

Parameters:

regionInfo - Region for which this selection is being done. nn

initialize

public void initialize()

Description copied from interface: LoadBalancer

Initialize the load balancer. Must be called after setters. n

Specified by:

initialize in interface LoadBalancer

regionOnline

public void regionOnline(RegionInfo regionInfo,
                         ServerName sn)

Description copied from interface: LoadBalancer

Marks the region as online at balancer. nn

Specified by:

regionOnline in interface LoadBalancer

regionOffline

public void regionOffline(RegionInfo regionInfo)

Description copied from interface: LoadBalancer

Marks the region as offline at balancer. n

Specified by:

regionOffline in interface LoadBalancer

onConfigurationChange

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

Description copied from interface: ConfigurationObserver

This method would be called by the ConfigurationManager object when the Configuration object is reloaded from disk.

Specified by:

onConfigurationChange in interface ConfigurationObserver

Specified by:

onConfigurationChange in interface LoadBalancer

postMasterStartupInitialize

public void postMasterStartupInitialize()

Description copied from interface: LoadBalancer

If balancer needs to do initialization after Master has started up, lets do that here.

Specified by:

postMasterStartupInitialize in interface LoadBalancer

updateBalancerStatus

public void updateBalancerStatus(boolean status)

Specified by:

updateBalancerStatus in interface LoadBalancer