org.apache.hadoop.util

Class NodeHealthScriptRunner

java.lang.Object

org.apache.hadoop.service.AbstractService

org.apache.hadoop.util.NodeHealthScriptRunner

All Implemented Interfaces:

Closeable, AutoCloseable, Service

public class NodeHealthScriptRunner
extends AbstractService

The class which provides functionality of checking the health of the node using the configured node health script and reporting back to the service for which the health checker has been asked to report.

Nested Class Summary

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

Service.STATE

Field Summary

Fields

Modifier and Type	Field and Description
static String	NODE_HEALTH_SCRIPT_TIMED_OUT_MSG Time out error message

Constructor Summary

Constructors

Constructor and Description
NodeHealthScriptRunner(String scriptName, long chkInterval, long timeout, String[] scriptArgs)

Method Summary

Methods

Modifier and Type	Method and Description
String	getHealthReport() Returns output from health script.
long	getLastReportedTime() Returns time stamp when node health script was last run.
TimerTask	getTimerTask() Used only by tests to access the timer task directly
boolean	isHealthy() Gets the if the node is healthy or not
protected void	serviceInit(Configuration conf) All initialization code needed by a service.
protected void	serviceStart() Method used to start the Node health monitoring.
protected void	serviceStop() Method used to terminate the node health monitoring service.
static boolean	shouldRun(String healthScript) Method used to determine if or not node health monitoring service should be started or not.

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

Field Detail

NODE_HEALTH_SCRIPT_TIMED_OUT_MSG

public static final String NODE_HEALTH_SCRIPT_TIMED_OUT_MSG

Time out error message

See Also:

Constant Field Values

Constructor Detail

NodeHealthScriptRunner

public NodeHealthScriptRunner(String scriptName,
                      long chkInterval,
                      long timeout,
                      String[] scriptArgs)

Method Detail

serviceInit

protected void serviceInit(Configuration conf)
                    throws Exception

Description copied from class: AbstractService

All initialization code needed by a service. This method will only ever be called once during the lifecycle of a specific service instance. Implementations do not need to be synchronized as the logic in AbstractService.init(Configuration) prevents re-entrancy. The base implementation checks to see if the subclass has created a new configuration instance, and if so, updates the base class value

Overrides:

serviceInit in class AbstractService

Parameters:

conf - configuration

Throws:

Exception - on a failure -these will be caught, possibly wrapped, and wil; trigger a service stop

serviceStart

protected void serviceStart()
                     throws Exception

Method used to start the Node health monitoring.

Overrides:

serviceStart in class AbstractService

Throws:

Exception - if needed -these will be caught, wrapped, and trigger a service stop

serviceStop

protected void serviceStop()

Method used to terminate the node health monitoring service.

Overrides:

serviceStop in class AbstractService

isHealthy

public boolean isHealthy()

Gets the if the node is healthy or not

Returns:

true if node is healthy

getHealthReport

public String getHealthReport()

Returns output from health script. if node is healthy then an empty string is returned.

Returns:

output from health script

getLastReportedTime

public long getLastReportedTime()

Returns time stamp when node health script was last run.

Returns:

timestamp when node health script was last run

shouldRun

public static boolean shouldRun(String healthScript)

Method used to determine if or not node health monitoring service should be started or not. Returns true if following conditions are met:

1. Path to Node health check script is not empty
2. Node health check script file exists

Returns:

true if node health monitoring service can be started.

getTimerTask

public TimerTask getTimerTask()

Used only by tests to access the timer task directly

Returns:

the timer task