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https://issues.apache.org/jira/browse/HADOOP-1857?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12533606
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Amareshwari Sri Ramadasu commented on HADOOP-1857:
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Both stdout and stderr of debug script can be redirected to debugout.
And we dont need $jobconf in the command, we should have $syslog.
bq. Doesn't the "file" command when run on a core file give the executable
name? Why does the executable need to be in the current working directory? That
doesn't sound right.
Here, executable has a symlink in the current working directory. We need to
have a symlink in current working directory or else we need to know the path of
executable from the framework and replace when needed. I feel a symlink is
better than finding the path and replacing when needed, as we need @program@ to
replace. The '#' is added in the config files for the pipes examples for
creating symlink.
bq. In terms of the parameters, it just seems like the script should have a
single interface rather than supporting a bunch of variables that the user can
put together.
The interface we have now supports for both submitting a command (without doing
any add cache file) and a script file if he wants.
Now, for pipes, we are adding the default debug command as 'gdb <program> -c
<core> -x <cmd-file>'. If we move this to a script, we do not know the
<program> in the script file, which would need <program> as argument for the
script. I feel the interface we have now has more flexibility to the user,
than single interface.
> Ability to run a script when a task fails to capture stack traces
> -----------------------------------------------------------------
>
> Key: HADOOP-1857
> URL: https://issues.apache.org/jira/browse/HADOOP-1857
> Project: Hadoop
> Issue Type: Improvement
> Components: mapred
> Affects Versions: 0.14.0
> Reporter: Amareshwari Sri Ramadasu
> Assignee: Amareshwari Sri Ramadasu
> Fix For: 0.15.0
>
> Attachments: patch-1857.txt, patch-1857.txt, patch-1857.txt,
> patch-1857.txt, patch1857.txt, tt-no-warn.patch
>
>
> This basically is for providing a better user interface for debugging failed
> jobs. Today we see stack traces for failed tasks on the job ui if the job
> happened to be a Java MR job. For non-Java jobs like Streaming, Pipes, the
> diagnostic info on the job UI is not helpful enough to debug what might have
> gone wrong. They are usually framework traces and not app traces.
> We want to be able to provide a facility, via user-provided scripts, for doing
> post-processing on task logs, input, output, etc. There should be some default
> scripts like running core dumps under gdb for locating illegal instructions,
> the last few lines from stderr, etc. These outputs could be sent to the
> tasktracker and in turn to the jobtracker which would then display it on the
> job UI on demand.
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