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Date: Wed, 21 Nov 2012 07:45:49 -0500
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Subject: Re: reducer not starting
From: Jean-Marc Spaggiari <jean-marc@spaggiari.org>
To: user@hadoop.apache.org
Content-Type: text/plain; charset=UTF-8

Just FYI, you don't need to stop the job, update the host, and retry.

Just update the host while the job is running and it should retry and restart.

I had a similar issue with one of my node where the hosts file were
not updated. After the updated it has automatically resume the work...

JM

2012/11/21, praveenesh kumar <praveenesh@gmail.com>:
> Sometimes its network issue, reducers are not able to find hostnames or IPs
> of the other machines. Make sure your /etc/hosts entries and hostnames are
> correct.
>
> Regards,
> Praveenesh
>
> On Tue, Nov 20, 2012 at 10:46 PM, Harsh J <harsh@cloudera.com> wrote:
>
>> Your mappers are failing (possibly a user-side error or an
>> environmental one) and are being reattempted by the framework (default
>> behavior, attempts 4 times to avoid transient failure scenario).
>>
>> Visit your job's logs in the JobTracker web UI, to find more
>> information on why your tasks fail.
>>
>> On Tue, Nov 20, 2012 at 10:22 PM, jamal sasha <jamalshasha@gmail.com>
>> wrote:
>> >
>> >
>> >
>> > I am not sure whats happening, but I wrote a simple mapper and reducer
>> > script.
>> >
>> >
>> >
>> > And I am testing it against a small dataset (like few lines long).
>> >
>> >
>> >
>> > For some reason reducer is just not starting.. and mapper is executing
>> again
>> > and again?
>> >
>> >
>> >
>> >     12/11/20 09:21:18 INFO streaming.StreamJob:  map 0%  reduce 0%
>> >
>> >     12/11/20 09:22:05 INFO streaming.StreamJob:  map 50%  reduce 0%
>> >
>> >     12/11/20 09:22:10 INFO streaming.StreamJob:  map 100%  reduce 0%
>> >
>> >     12/11/20 09:32:05 INFO streaming.StreamJob:  map 50%  reduce 0%
>> >
>> >     12/11/20 09:32:11 INFO streaming.StreamJob:  map 0%  reduce 0%
>> >
>> >     12/11/20 09:32:20 INFO streaming.StreamJob:  map 50%  reduce 0%
>> >
>> >     12/11/20 09:32:31 INFO streaming.StreamJob:  map 100%  reduce 0%
>> >
>> >     12/11/20 09:42:20 INFO streaming.StreamJob:  map 50%  reduce 0%
>> >
>> >     12/11/20 09:42:31 INFO streaming.StreamJob:  map 0%  reduce 0%
>> >
>> >     12/11/20 09:42:32 INFO streaming.StreamJob:  map 50%  reduce 0%
>> >
>> >     12/11/20 09:42:50 INFO streaming.StreamJob:  map 100%  reduce 0%
>> >
>> >
>> >
>> >
>> >
>> > Let me know if you want the code also.
>> >
>> > Any clues of where I am going wrong?
>> >
>> > Thanks
>> >
>> >
>> >
>> >
>> >
>> >
>>
>>
>>
>> --
>> Harsh J
>>
>