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MapReduce >> mail # user >> reducer not starting


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jamal sasha 2012-11-20, 16:52
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Harsh J 2012-11-20, 17:16
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praveenesh kumar 2012-11-21, 12:00
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Re: reducer not starting
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 <[EMAIL PROTECTED]>:
> 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 <[EMAIL PROTECTED]> 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 <[EMAIL PROTECTED]>
>> 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
>>
>
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jamal sasha 2012-11-21, 14:36