Package org.apache.hadoop.hbase.master.balancer

Class MaintenanceLoadBalancer

java.lang.Object

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

All Implemented Interfaces:

ConfigurationObserver, LoadBalancer, Stoppable

@Private
public class MaintenanceLoadBalancer
extends Object
implements LoadBalancer

a balancer which is only used in maintenance mode.

Field Summary

Fields

Modifier and Type	Field	Description
private boolean	stopped

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

BOGUS_SERVER_NAME, HBASE_RSGROUP_LOADBALANCER_CLASS

Constructor Summary

Constructors

Constructor	Description
MaintenanceLoadBalancer()

Method Summary

Modifier and Type	Method	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)	Notification that config has changed
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
Map<ServerName,List<RegionInfo>>	roundRobinAssignment(List<RegionInfo> regions, List<ServerName> servers)	Perform a Round Robin assignment of regions.
void	setClusterInfoProvider(ClusterInfoProvider provider)	Set the cluster info provider.
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

updateBalancerLoadInfo

Field Details

stopped

private volatile boolean stopped

Constructor Details

MaintenanceLoadBalancer

public MaintenanceLoadBalancer()

Method Details

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

setClusterInfoProvider

public void setClusterInfoProvider(ClusterInfoProvider provider)

Description copied from interface: LoadBalancer

Set the cluster info provider. Usually it is just a wrapper of master.

Specified by:

setClusterInfoProvider 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)
                                                      throws IOException

Description copied from interface: LoadBalancer

Perform a Round Robin assignment of regions.

Specified by:

roundRobinAssignment in interface LoadBalancer

Returns:

Map of servername to regioninfos

Throws:

IOException

retainAssignment

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

Description copied from interface: LoadBalancer

Assign regions to the previously hosting region server

Specified by:

retainAssignment in interface LoadBalancer

Returns:

List of plans

Throws:

IOException

randomAssignment

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

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.

Throws:

IOException

initialize

public void initialize()

Description copied from interface: LoadBalancer

Initialize the load balancer. Must be called after setters.

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.

Specified by:

regionOnline in interface LoadBalancer

regionOffline

public void regionOffline(RegionInfo regionInfo)

Description copied from interface: LoadBalancer

Marks the region as offline at balancer.

Specified by:

regionOffline in interface LoadBalancer

onConfigurationChange

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

Description copied from interface: LoadBalancer

Notification that config has changed

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