Package org.apache.hadoop.hdfs.server.federation.router

Class NamenodeHeartbeatService

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.hadoop.hdfs.server.federation.router.PeriodicService

org.apache.hadoop.hdfs.server.federation.router.NamenodeHeartbeatService

All Implemented Interfaces:

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

public class NamenodeHeartbeatService
extends PeriodicService

The Router periodically checks the state of a Namenode (usually on the same server) and reports their high availability (HA) state and load/space status to the StateStoreService . Note that this is an optional role as a Router can be independent of any subcluster.

For performance with Namenode HA, the Router uses the high availability state information in the State Store to forward the request to the Namenode that is most likely to be active.

Note that this service can be embedded into the Namenode itself to simplify the operation.

Nested Class Summary

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

org.apache.hadoop.service.Service.STATE

Constructor Summary

Constructors

Constructor	Description
NamenodeHeartbeatService(ActiveNamenodeResolver resolver, String nsId, String nnId)	Create a new Namenode status updater.
NamenodeHeartbeatService(ActiveNamenodeResolver resolver, String nsId, String nnId, String resolvedHost)	Create a new Namenode status updater.

Method Summary

Modifier and Type	Method	Description
String	getNamenodeDesc()	Get the description of the Namenode to monitor.
protected NamenodeStatusReport	getNamenodeStatusReport()	Get the status report for the Namenode monitored by this heartbeater.
void	periodicInvoke()	Method that the service will run periodically.
protected void	serviceInit(org.apache.hadoop.conf.Configuration configuration)
protected void	serviceStop()

Methods inherited from class org.apache.hadoop.hdfs.server.federation.router.PeriodicService

getErrorCount, getIntervalMs, getLastUpdate, getRunCount, serviceStart, setIntervalMs, startPeriodic, stopPeriodic

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 Details

NamenodeHeartbeatService

public NamenodeHeartbeatService(ActiveNamenodeResolver resolver,
 String nsId,
 String nnId)

Create a new Namenode status updater.

Parameters:

resolver - Namenode resolver service to handle NN registration.

nsId - Identifier of the nameservice.

nnId - Identifier of the namenode in HA.

NamenodeHeartbeatService

public NamenodeHeartbeatService(ActiveNamenodeResolver resolver,
 String nsId,
 String nnId,
 String resolvedHost)

Create a new Namenode status updater.

Parameters:

resolver - Namenode resolver service to handle NN registration.

nsId - Identifier of the nameservice.

nnId - Identifier of the namenode in HA.

resolvedHost - resolvedHostname for this specific namenode.

Method Details

serviceInit

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

Overrides:

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

Throws:

Exception

periodicInvoke

public void periodicInvoke()

Description copied from class: PeriodicService

Method that the service will run periodically.

Specified by:

periodicInvoke in class PeriodicService

getNamenodeStatusReport

protected NamenodeStatusReport getNamenodeStatusReport()

Get the status report for the Namenode monitored by this heartbeater.

Returns:

Namenode status report.

getNamenodeDesc

public String getNamenodeDesc()

Get the description of the Namenode to monitor.

Returns:

Description of the Namenode to monitor.

serviceStop

protected void serviceStop()
                    throws Exception

Overrides:

serviceStop in class PeriodicService

Throws:

Exception