Where does hadoop mapreduce framework send my System.out.print() statements ? (stdout)

Question

I want to debug a mapreduce script, and without going into much trouble tried to put some print statements in my program. But I cant seem to find them in any of the logs.

Answer 1

Another way is through the terminal:

1) Go into your Hadoop_Installtion directory, then into "logs/userlogs".
2) Open your job_id directory.
3) Check directories with _m_ if you want the mapper output or _r_ if you're looking for reducers.

Example: In Hadoop-20.2.0:

> ls ~/hadoop-0.20.2/logs/userlogs/attempt_201209031127_0002_m_000000_0/
log.index   stderr      stdout      syslog

The above means:
Hadoop_Installation: ~/hadoop-0.20.2
job_id: job_201209031127_0002
_m_: map task , "map number": _000000_

4) open stdout if you used "system.out.println" or stderr if you used "system.err.append".

PS. other hadoop versions might have a sight different hierarchy but they're all should be under $Hadoop_Installtion/logs/userlogs.