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MapReduce >> mail # user >> How to change topology

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Re: How to change topology
On 9 October 2012 16:51, Shinichi Yamashita <[EMAIL PROTECTED]> wrote:

> Hi Steve,
> Thank you for your reply.
> > no, it's the Namenode and JobTracker that needs to be restarted;
> > they are the bits that care where the boxes are.
> I confirmed it in my cluster, and I understood it as follows.
> First, the resolved node information is recorded in ConcurrentHashMap.
> Next same node toplogy decision, HashMap data is given priority to over a
> script.
> The HashMap data become invalid by restart of NameNode and JobTracker.

That's right. There's been lots of discussion on adding live topology

There's also a large unfinished JIRA in my name to do better topology work
in Hadoop 2,

Including the ability to do local checks of a topology script

Supporting topology dump and reset from any of the manager nodes would come