[
https://issues.apache.org/jira/browse/HADOOP-4490?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12655673#action_12655673
]
Hemanth Yamijala commented on HADOOP-4490:
------------------------------------------
I have a version now that runs with JVM reuse enabled also. The main changes to
get this to work was to correct the way I was figuring out the current task ids
in the JvmManager class.
Also added a KILL_TASK command. This will look as follows:
KILL_TASK user_name job_id task_attempt_id
This will be called from JvmRunner.kill(), which in turn is called whenever a
TT gets a kill task action. Since the JVM process is running as the job owner
(different from the TT), we can't directly destroy the JVM process. Instead,
what I've done is the following:
- Write a (hidden) .pid file into the task directory when a task is executed.
This is owned by the job owner and not readable by anyone else. The pid file
contains the JVM's pid.
- When the JVM needs to be killed, we call the taskcontroller executable with
the job_id and task_id.
- The taskcontroller drops privileges to the job owner, then reads the pid file
and gets the pid of the jvm.
- Then the taskcontroller issues a kill(pid, SIGTERM) to kill the jvm.
Any concerns with this approach ?
Currently other than distributed cache, all other aspects of the task life
cycle are functioning. I'll probably upload a single writeup (as Arun had done
for HADOOP-4348) that will capture all the information in comments above for
easy reference.
And of course, follow that up with the first patch. *smile*
> Map and Reduce tasks should run as the user who submitted the job
> -----------------------------------------------------------------
>
> Key: HADOOP-4490
> URL: https://issues.apache.org/jira/browse/HADOOP-4490
> Project: Hadoop Core
> Issue Type: Sub-task
> Components: mapred, security
> Reporter: Arun C Murthy
> Assignee: Hemanth Yamijala
>
> Currently the TaskTracker spawns the map/reduce tasks, resulting in them
> running as the user who started the TaskTracker.
> For security and accounting purposes the tasks should be run as the job-owner.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
