org.apache.hadoop.yarn.server.api

Class ConfigurableAuxServices

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.hadoop.yarn.server.api.ConfigurableAuxServices

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.hadoop.service.Service, org.apache.hadoop.service.ServiceStateChangeListener

public class ConfigurableAuxServices
extends org.apache.hadoop.service.AbstractService
implements org.apache.hadoop.service.ServiceStateChangeListener

Manages a set of @link{ConfigurableAuxiliaryService} instances by starting and stopping them. It takes a parameter auxServicesPropName and uses it to determine the auxiliary service classes to instantiate. Since this is meant to be an extensibility feature, the calling code should add this instance as the first one to its service list. This will ensure that the externally plugged in services are initialized first as they may be setting up critical resources on top of which rest of the stack should be built. For e.g., an external service might try to create volumes on top of which directories need to be created. Note: The code has been taken from @link{AuxServices}.

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.hadoop.service.Service

org.apache.hadoop.service.Service.STATE

Constructor Summary

Constructors

Constructor and Description
ConfigurableAuxServices(String name, String auxServicesPropName)

Method Summary

Methods

Modifier and Type	Method and Description
void	serviceInit(org.apache.hadoop.conf.Configuration conf)
void	serviceStart()
void	serviceStop()
void	stateChanged(org.apache.hadoop.service.Service service)

Methods inherited from class org.apache.hadoop.service.AbstractService

close, getBlockers, getConfig, getFailureCause, getFailureState, getLifecycleHistory, getName, getServiceState, getStartTime, init, isInState, noteFailure, putBlocker, registerGlobalListener, registerServiceListener, removeBlocker, setConfig, start, stop, toString, unregisterGlobalListener, unregisterServiceListener, waitForServiceToStop

Methods inherited from class java.lang.Object

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

Constructor Detail

ConfigurableAuxServices

public ConfigurableAuxServices(String name,
                       String auxServicesPropName)

Method Detail

serviceInit

public void serviceInit(org.apache.hadoop.conf.Configuration conf)
                 throws Exception

Overrides:

serviceInit in class org.apache.hadoop.service.AbstractService

Throws:

Exception

serviceStart

public void serviceStart()
                  throws Exception

Overrides:

serviceStart in class org.apache.hadoop.service.AbstractService

Throws:

Exception

serviceStop

public void serviceStop()
                 throws Exception

Overrides:

serviceStop in class org.apache.hadoop.service.AbstractService

Throws:

Exception

stateChanged

public void stateChanged(org.apache.hadoop.service.Service service)

Specified by:

stateChanged in interface org.apache.hadoop.service.ServiceStateChangeListener