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From "Jamack, Peter" <PJam...@consilium1.com>
Subject Re: Dynamic changing of slaves
Date Tue, 21 Feb 2012 23:21:44 GMT
Yeah, I'm not sure how you can actually do it, as I haven't done it
before, but from a logical perspective,  you'd probably have to do a lot
of configuration changes and maybe even write up some complicated M/R
code, coordination/rules engine logic, change how the heartbeat &
scheduler operate to do what you want.
 There might be an easier way, I'm not sure though.

Peter J

On 2/21/12 3:16 PM, "Merto Mertek" <masmertoz@gmail.com> wrote:

>I think that job configuration does not allow you such setup, however
>I missed something..
> Probably I would tackle this problem from the scheduler source. The
>default one is JobQueueTaskScheduler which preserves a fifo based queue.
>When a tasktracker (your slave) tells the jobtracker that it has some free
>slots to run, JT in the heartbeat method calls the scheduler assignTasks
>method where tasks are assigned on local basis. In other words, scheduler
>tries to find tasks on the tasktracker which data resides on it. If the
>scheduler will not find a local map/reduce task to run it will try to find
>a non local one. Probably here is the point where you should do something
>with your jobs and wait for the tasktrackers heartbeat.. Instead of
>for the TT heartbeat, maybe there is another option to force an
>heartbeatResponse, despite the TT has not send a heartbeat but I am not
>aware of it..
>On 21 February 2012 19:27, theta <glynisdsouza@email.arizona.edu> wrote:
>> Hi,
>> I am working on a project which requires a setup as follows:
>> One master with four slaves.However, when a map only program is run, the
>> master dynamically selects the slave to run the map. For example, when
>> program is run for the first time, slave 2 is selected to run the map
>> reduce programs, and the output is stored on dfs. When the program is
>> the second time, slave 3 is selected and son on.
>> I am currently using Hadoop 0.20.2 with Ubuntu 11.10.
>> Any ideas on creating the setup as described above?
>> Regards
>> --
>> View this message in context:
>> Sent from the Hadoop core-user mailing list archive at Nabble.com.

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