You can't do this currently at all.
At a minimum you need a custom scheduler and you need to do more work
on the JT for this to happen.
I still haven't seen a good enough reason for this 'feature' in nearly
5 years.
Arun
On Dec 18, 2010, at 10:24 AM, Jane Chen wrote:
But how does this help me request which host to schedule the reduce
task to?
Thanks,
Jane
--- On Sat, 12/18/10, Hari Sreekumar <hsreeku...@clickable.com> wrote:
From: Hari Sreekumar <hsreeku...@clickable.com>
Subject: Re: How to Influence Reduce Task Location.
To: mapreduce-user@hadoop.apache.org
Date: Saturday, December 18, 2010, 10:16 AM
Hi Jane,
The partitioner class can be used to achieve this. (http://hadoop.apache.org/mapreduce/docs/r0.21.0/api/org/apache/hadoop/mapreduce/Partitioner.html
).
Thanks,
Hari
On Sat, Dec 18, 2010 at 11:13 PM, Jane Chen
<jxchen_us_1...@yahoo.com> wrote:
Hi All,
Is there anyway to influence where a reduce task is run? We have a
case where we'd like to choose the host to run the reduce task based
on the task's input key.
Any suggestion is greatly appreciated.
Thanks,
Jane
