Sorry,I should have mentioned that - this I want to do without the code change.

Something like - I have the cluster up and running and suddenly I realize that 
forgot to add some properties in the hadoop-site.xml file.  Now I can add these 
new properties - but how do these take into effect ? Without re-starting the 
cluster (which is in production and customer wouldn't like that either :-) )

Thanks!
Arvind




________________________________
From: Jakob Homan <[email protected]>
To: [email protected]
Sent: Thursday, August 13, 2009 2:04:43 PM
Subject: Re: How to re-read the config files

Hey Arvind-
   You'll probably want to look at the Configuration.reload() method, as 
demonstrated:

public class TestReloadConfig {
  public static void main(String[] args) throws IOException {
    Configuration conf = new Configuration();
    FileSystem fs = FileSystem.get(conf); // pull in dfs settings

    System.out.println("Replication = " + conf.get("dfs.replication"));
    System.out.println("Update file and press <enter>");
    new Scanner(System.in).nextLine();

    conf.reloadConfiguration();
    System.out.println("Now replication = " + conf.get("dfs.replication"));
  }
}

Note from the Javadoc: Values that are added via set methods will overlay 
values read from the resources.

Hope this helps.  Write back if you have more questions.

Thanks,
Jakob Homan
Hadoop at Yahoo!


Arvind Sharma wrote:
> Hi,
> 
> I was wondering if there is way to let Hadoop re-read the config file 
> (hadoop-site.xml) after  making some changes in it.
> 
> I don't want to restart the whole cluster for that.
> 
> I am using Hadoop 0.19.2
> 
> Thanks!
> Arvind
> 
> 
> 
>      


      

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