NN refers to the rack topology script/class when a new node joins
(i.e. it doesn't have the node's IP already in cache), when it starts
up, and (I think) also when you issue -refreshNodes.

The ideal way to "add" a node to the rack right now is to first update
the rack config at the NN, then boot the DN up.

On Thu, Feb 21, 2013 at 1:47 AM, Chris Embree <[EMAIL PROTECTED]> wrote:
> I've checked all of the documentation, books and google searches I can think
> of....
>
> I have a working topology script.  I have dynamic IP's.  I have an automated
> process to update the rack data when a datanode changes IP.
>
> What I don't have is any clue as to when the NN reads this script.  If I
> execute it right now with 10.10.10.10 it'll return /dc1/rack3  When I run
> hadoop balancer I see /default/rack/10.10.10.10:50010
> I really don't want to have to restart the NN for IP changes to be noticed.
>
> Any brilliant insights?
>
> Thanks
> Chris

--
Harsh J

I'd submitted a patch(HADOOP-8928.txt) to reload topology config dynamically like "hdfs dfsadmin -refreshTopology" style several months before, see HADOOP-8928 for more details.

Regards,
Liang
________________________________
发件人: Chris Embree [[EMAIL PROTECTED]]
发送时间: 2013年2月21日 4:17
收件人: [EMAIL PROTECTED]
主题: Topology script frequency

I've checked all of the documentation, books and google searches I can think of....

I have a working topology script.  I have dynamic IP's.  I have an automated process to update the rack data when a datanode changes IP.

What I don't have is any clue as to when the NN reads this script.  If I execute it right now with 10.10.10.10 it'll return /dc1/rack3  When I run hadoop balancer I see /default/rack/10.10.10.10:50010<http://10.10.10.10:50010>
I really don't want to have to restart the NN for IP changes to be noticed.

Any brilliant insights?

Thanks
Chris