org.apache.hadoop.mapred
Class DefaultTaskController

java.lang.Object
  extended by org.apache.hadoop.mapred.TaskController
      extended by org.apache.hadoop.mapred.DefaultTaskController
All Implemented Interfaces:
Configurable

public class DefaultTaskController
extends TaskController

The default implementation for controlling tasks. This class provides an implementation for launching and killing tasks that need to be run as the tasktracker itself. Hence, many of the initializing or cleanup methods are not required here.
NOTE: This class is internal only class and not intended for users!!


Field Summary
 
Fields inherited from class org.apache.hadoop.mapred.TaskController
allocator, COMMAND_FILE, localStorage, TASK_LAUNCH_SCRIPT_PERMISSION
 
Constructor Summary
DefaultTaskController()
           
 
Method Summary
 void createLogDir(TaskAttemptID taskID, boolean isCleanup)
          Creates task log dir
 void deleteAsUser(String user, String subDir)
          Delete the user's files under all of the task tracker root directories.
 void deleteLogAsUser(String user, String subDir)
          Delete the user's files under the userlogs directory.
 void initializeJob(String user, String jobid, Path credentials, Path jobConf, TaskUmbilicalProtocol taskTracker, InetSocketAddress ttAddr)
          This routine initializes the local file system for running a job.
 int launchTask(String user, String jobId, String attemptId, List<String> setup, List<String> jvmArguments, File currentWorkDirectory, String stdout, String stderr)
          Create all of the directories for the task and launches the child jvm.
 void setConf(Configuration conf)
          Set the configuration to be used by this object.
 void setup(LocalDirAllocator allocator, org.apache.hadoop.mapred.TaskTracker.LocalStorage localStorage)
          Does initialization and setup.
 void signalTask(String user, int taskPid, ProcessTree.Signal signal)
          Send a signal to a task pid as the user.
 void truncateLogsAsUser(String user, List<Task> allAttempts)
          Run the passed command as the user
 
Methods inherited from class org.apache.hadoop.mapred.TaskController
getConf, getLocalDirs, getRunAsUser, logOutput, writeCommand
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

DefaultTaskController

public DefaultTaskController()
Method Detail

setConf

public void setConf(Configuration conf)
Description copied from interface: Configurable
Set the configuration to be used by this object.

Specified by:
setConf in interface Configurable
Overrides:
setConf in class TaskController

createLogDir

public void createLogDir(TaskAttemptID taskID,
                         boolean isCleanup)
                  throws IOException
Description copied from class: TaskController
Creates task log dir

Specified by:
createLogDir in class TaskController
Parameters:
taskID - ID of the task
isCleanup - If the task is cleanup task or not
Throws:
IOException

launchTask

public int launchTask(String user,
                      String jobId,
                      String attemptId,
                      List<String> setup,
                      List<String> jvmArguments,
                      File currentWorkDirectory,
                      String stdout,
                      String stderr)
               throws IOException
Create all of the directories for the task and launches the child jvm.

Specified by:
launchTask in class TaskController
Parameters:
user - the user name
attemptId - the attempt id
jobId - the jobId in question
setup - list of shell commands to execute before the jvm
jvmArguments - list of jvm arguments
currentWorkDirectory - the full path of the cwd for the task
stdout - the file to redirect stdout to
stderr - the file to redirect stderr to
Returns:
the exit code for the task
Throws:
IOException

initializeJob

public void initializeJob(String user,
                          String jobid,
                          Path credentials,
                          Path jobConf,
                          TaskUmbilicalProtocol taskTracker,
                          InetSocketAddress ttAddr)
                   throws IOException,
                          InterruptedException
This routine initializes the local file system for running a job. Details: This method must be invoked in the access control context of the job owner user. This is because the distributed cache is also setup here and the access to the hdfs files requires authentication tokens in case where security is enabled.

Specified by:
initializeJob in class TaskController
Parameters:
user - the user in question (the job owner)
jobid - the ID of the job in question
credentials - the path to the credentials file that the TaskTracker downloaded
jobConf - the path to the job configuration file that the TaskTracker downloaded
taskTracker - the connection to the task tracker
ttAddr - the tasktracker's RPC address
Throws:
IOException
InterruptedException

signalTask

public void signalTask(String user,
                       int taskPid,
                       ProcessTree.Signal signal)
Description copied from class: TaskController
Send a signal to a task pid as the user.

Specified by:
signalTask in class TaskController
Parameters:
user - the user name
taskPid - the pid of the task
signal - the id of the signal to send

deleteAsUser

public void deleteAsUser(String user,
                         String subDir)
                  throws IOException
Delete the user's files under all of the task tracker root directories.

Specified by:
deleteAsUser in class TaskController
Parameters:
user - the user name
subDir - the path relative to the user's subdirectory under the task tracker root directories.
Throws:
IOException

deleteLogAsUser

public void deleteLogAsUser(String user,
                            String subDir)
                     throws IOException
Delete the user's files under the userlogs directory.

Specified by:
deleteLogAsUser in class TaskController
Parameters:
user - the user to work as
subDir - the path under the userlogs directory.
Throws:
IOException

truncateLogsAsUser

public void truncateLogsAsUser(String user,
                               List<Task> allAttempts)
                        throws IOException
Description copied from class: TaskController
Run the passed command as the user

Specified by:
truncateLogsAsUser in class TaskController
allAttempts - the list of attempts that the JVM ran
Throws:
IOException

setup

public void setup(LocalDirAllocator allocator,
                  org.apache.hadoop.mapred.TaskTracker.LocalStorage localStorage)
Description copied from class: TaskController
Does initialization and setup.

Specified by:
setup in class TaskController
Parameters:
allocator - the local dir allocator to use
localStorage - local storage to obtain dirs from


Copyright © 2009 The Apache Software Foundation