There are multiple ways to debug map reduce programs. I found comfortable using the jobtracker web UI. You can your job tracker web UI at
Open it in a browser.
There you can find the running,failed and retired jobs. You can drill down on any job to task tracker log levels from there.
Mostly I get the root cause of my job failures from there.
Hope it helps
Bejoy K S
From: <[EMAIL PROTECTED]>
Date: Thu, 15 Sep 2011 09:39:23
To: <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
Subject: Debugging Mapreduce programs
Can we use sysouts in java to debug MR programs.
Where would those sysouts be printed?
What would be the best way to debug a remote system where I have access
to the machine only through putty.
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