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From "zhu weimin" <xim-...@tsm.kddilabs.jp>
Subject RE: How to dynamically remove a tasktracker?
Date Tue, 20 Apr 2010 01:35:53 GMT
>$HADOOP_HOME/bin/hadoop mradmin -refreshNodes 

The command doesn't exist.

# hadoop mradmin -refreshNodes

refreshNodes: Unknown command

Usage: java MRAdmin


           [-help [cmd]]


I using hadoop-0.20.2


From: Ramya R [mailto:rramya@yahoo-inc.com] 
Sent: Thursday, April 15, 2010 2:01 PM
To: mapreduce-user@hadoop.apache.org; rold_50@yahoo.com
Subject: Re: How to dynamically remove a tasktracker?


Hi Harold,

Apart from killing the TT process, you can also follow the below steps to
remove a TT:

1.	In mapred-site.xml, configure the "mapred.hosts.exclude" to have the
full path to a file (say excludeTTfile) which will contain the list of TTs
you want to remove. 
2.	Populate excludeTTfile with the list of TTs you want to remove 
3.	$HADOOP_HOME/bin/hadoop mradmin -refreshNodes 
4.	This will shutdown the TTs listed in excludeTTfile and JT will
immediately remove them from active TTs list.

Hope this helps

On 4/15/10 12:46 AM, "Harold Lim" <rold_50@yahoo.com> wrote:

Hi All,

How do I dynamically remove a tasktracker? Do I simply kill the tasktracker
process, and the namenode will detect it? Or is there a graceful way of
doing it?



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