org.apache.hadoop.yarn.applications.distributedshell

Class Client

java.lang.Object

org.apache.hadoop.yarn.applications.distributedshell.Client

@InterfaceAudience.Public
 @InterfaceStability.Unstable
public class Client
extends Object

Client for Distributed Shell application submission to YARN.

The distributed shell client allows an application master to be launched that in turn would run the provided shell command on a set of containers.

This client is meant to act as an example on how to write yarn-based applications.

To submit an application, a client first needs to connect to the ResourceManager aka ApplicationsManager or ASM via the ApplicationClientProtocol. The ApplicationClientProtocol provides a way for the client to get access to cluster information and to request for a new ApplicationId.

For the actual job submission, the client first has to create an ApplicationSubmissionContext. The ApplicationSubmissionContext defines the application details such as ApplicationId and application name, the priority assigned to the application and the queue to which this application needs to be assigned. In addition to this, the ApplicationSubmissionContext also defines the ContainerLaunchContext which describes the Container with which the ApplicationMaster is launched.

The ContainerLaunchContext in this scenario defines the resources to be allocated for the ApplicationMaster's container, the local resources (jars, configuration files) to be made available and the environment to be set for the ApplicationMaster and the commands to be executed to run the ApplicationMaster.

Using the ApplicationSubmissionContext, the client submits the application to the ResourceManager and then monitors the application by requesting the ResourceManager for an ApplicationReport at regular time intervals. In case of the application taking too long, the client kills the application by submitting a KillApplicationRequest to the ResourceManager.

Field Summary

Fields

Modifier and Type	Field and Description
static String	SCRIPT_PATH

Constructor Summary

Constructors

Constructor and Description
Client()
Client(Configuration conf)

Method Summary

Modifier and Type	Method and Description
boolean	init(String[] args) Parse command line options
static void	main(String[] args)
boolean	run() Main run function for the client
protected void	sendStopSignal()

Methods inherited from class java.lang.Object

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

Field Detail

SCRIPT_PATH

public static final String SCRIPT_PATH

See Also:

Constant Field Values

Constructor Detail

Client

public Client(Configuration conf)
       throws Exception

Throws:

Exception

Client

public Client()
       throws Exception

Throws:

Exception

Method Detail

main

public static void main(String[] args)

Parameters:

args - Command line arguments

init

public boolean init(String[] args)
             throws org.apache.commons.cli.ParseException

Parse command line options

Parameters:

args - Parsed command line options

Returns:

Whether the init was successful to run the client

Throws:

org.apache.commons.cli.ParseException

run

public boolean run()
            throws IOException,
                   YarnException

Main run function for the client

Returns:

true if application completed successfully

Throws:

IOException

YarnException

sendStopSignal

protected void sendStopSignal()