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From Alberto Luengo Cabanillas <cabi...@gmail.com>
Subject Re: Displaying Map output in MapReduce
Date Fri, 02 Jul 2010 07:32:37 GMT
Hi! Supposing that you´re using a virtualized environment, you should be
able to get to JobTracker Web Admin Interface from http://<your_virtualized_
machine_ip>:50070/logs/userlogs. In case you´re running Hadoop from inside a
cluster frontend, use this machine´s IP. Inside this directory, it will
exist another one called "userlogs" where you will see all map and reduce
tasks launch by the JobTracker and the TaskTrackers. These tasks will look
like 'job_[m,r]_0_xxxxxx' (or similar). Inside of every one of them there
will be three subdirectories (stdout, stdlog and stderr) which will contain
all your debugging messages.
Inside my MapReduce development programs I use the Java *LOG* class in a
sentence like this:

private static final Log LOG =
LogFactory.getLog(<your_class_name>.class.getName());
LOG.info("***********INSIDE MY REDUCER SETUP**********");

Besides these messages, a normal "System.out.println(...)" will also appear
in the above directories.

Hope it helps!

2010/7/2 abc xyz <fabc_xyz111@yahoo.com>

> Hi folks,
>
> I want to just display the output of my mapper on console or want to log it
> in
> some file. System.out.println and Log4j's logger are not displaying the
> output.
> How can I see the intermediate results?
>
> Cheers
>
>
>






-- 
Alberto

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