org.apache.drill.yarn.core

Class LaunchSpec

java.lang.Object

org.apache.drill.yarn.core.LaunchSpec

Direct Known Subclasses:

AppSpec

public class LaunchSpec
extends Object

Abstract description of a remote process launch that describes the many details needed to launch a process on a remote node.

Based on Simple YARN App.

Field Summary

Fields

Modifier and Type	Field and Description
List<String>	classPath Set to the application-specific class path for the Java application.
List<String>	cmdArgs Arguments to the remote command.
String	command Set to the name of the OS command to run when we wish to run a non-Java command.
Map<String,String>	env Defines environment variables to be set on the remote host before launching the remote app.
String	mainClass Set to the name of the Java main class (the one with the main method) when we wish to run a Java command.
Map<String,org.apache.hadoop.yarn.api.records.LocalResource>	resources List of (key, file) pairs to be localized to the node before running the command.
List<String>	vmArgs Optional VM arguments to pass to the JVM when running a Java class; ignored when running an OS command.

Constructor Summary

Constructors

Constructor and Description
LaunchSpec()

Method Summary

Modifier and Type	Method and Description
org.apache.hadoop.yarn.api.records.ContainerLaunchContext	createLaunchContext(org.apache.hadoop.yarn.conf.YarnConfiguration conf) Given this generic description of an application, create the detailed YARN application submission context required to launch the application.
void	dump(PrintStream out)
String	getCommand() Create the command line to run on the remote node.

Methods inherited from class java.lang.Object

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

Field Detail

resources

public Map<String,org.apache.hadoop.yarn.api.records.LocalResource> resources

List of (key, file) pairs to be localized to the node before running the command. The file must exist in a distributed file system (such as HDFS) visible to both the client and remote node. Typically, the path is relative or absolute within the file system defined by the fs.defaultFS parameter in core-site.xml.

TODO: Can the value also be a URL such as

hdfs://somehost:1234//path/to/file

The key is used as (what?).

env

public Map<String,String> env

Defines environment variables to be set on the remote host before launching the remote app. Note: do not set CLASSPATH here; use classPath instead.

command

public String command

Set to the name of the OS command to run when we wish to run a non-Java command.

mainClass

public String mainClass

Set to the name of the Java main class (the one with the main method) when we wish to run a Java command.

classPath

public List<String> classPath

Set to the application-specific class path for the Java application. These values are added to the Hadoop-provided values. These items are relative to (what?), use (what variables) to refer to the localized application directory.

vmArgs

public List<String> vmArgs

Optional VM arguments to pass to the JVM when running a Java class; ignored when running an OS command.

cmdArgs

public List<String> cmdArgs

Arguments to the remote command.

Constructor Detail

LaunchSpec

public LaunchSpec()

Method Detail

getCommand

public String getCommand()

Create the command line to run on the remote node. The command can either be a simple OS command (if the command member is set) or can be a Java class (if the mainClass member is set. If the command is Java, then we pass along optional Java VM arguments.

In all cases we append arguments to the command itself, and redirect stdout and stderr to log files.

Returns:

the complete command string

createLaunchContext

public org.apache.hadoop.yarn.api.records.ContainerLaunchContext createLaunchContext(org.apache.hadoop.yarn.conf.YarnConfiguration conf)
                                                                              throws IOException

Given this generic description of an application, create the detailed YARN application submission context required to launch the application.

Parameters:

conf - the YARN configuration obtained by reading the Hadoop configuration files

Returns:

the completed application launch context for the given application

Throws:

IOException - if localized resources are not found in the distributed file system (such as HDFS)

dump

public void dump(PrintStream out)