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From "Mikhail Yakshin" <greycat.na....@gmail.com>
Subject Re: Slaves "Hot-Swaping"
Date Tue, 02 Sep 2008 15:58:38 GMT
On Tue, Sep 2, 2008 at 7:33 PM, Camilo Gonzalez wrote:
> I was wondering if there is a way to "Hot-Swap" Slave machines, for example,
> in case an Slave machine fails while the Cluster is running and I want to
> mount a new Slave machine to replace the old one, is there a way to tell the
> Master that a new Slave machine is Online without having to stop and start
> again the Cluster?

You don't have to restart entire cluster, you just have to run
datanode (DFS support) and/or tasktracker processes on fresh node. You
can do it using hadoop-daemon.sh, commands are "start datanode" and
"start tasktracker" respectively. There's no need for "hot swapping"
and "replacing" old slave machines with new ones pretending to be old
ones. You just plug new one in with new IP/hostname and it will
eventually start to do tasks as all other nodes.

You don't really need any "hot standby" or any other high-availability
schemes. You just plug all possible slaves in and it will balance
everything out.

WBR, Mikhail Yakshin

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