Package org.apache.hadoop.yarn.applications.distributedshell

Class Client

java.lang.Object
org.apache.hadoop.yarn.applications.distributedshell.Client
@Public @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 Details

  • Constructor Details

  • Method Details

    • 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

      @VisibleForTesting protected void sendStopSignal()