I think it would be easier to add the production machines to the cluster one
by one and then remove the pre-production ZK instances from the cluster one
by one.

This gives you continuity that you lack otherwise.  Adding machines is a
matter of changing the configuration on each ZK and restarting ZK on that
machine.  You could add the machines in a lump if you don't add so many as
to prevent the cluster from having a quorum.  The configuration change and
restart can be easily scripted and goes quite quickly.

After the hand-off, you can bring the pre-production machines machines back
up with a smaller cluster configuration.

Of course, this trick only works if you have no production ZK already in
place so it won't work the second time around.  It is also a bit unusual for
the complete state of a pre-production staging cluster to be important
enough to preserve.

On Mon, May 4, 2009 at 10:35 AM, Satish Bhatti <cthd2...@gmail.com> wrote:

> ... (2) At some point, we want to switch the preproduction instance to be
> the
> production instance.  For the ZooKeeper servers, we will copy the data +
> logs directories from the pre machines currently running ZooKeeper to the
> prod machines that will be running ZooKeeper, and start up ZooKeeper on
> those machines.  Is this all that is necessary so that the new ZooKeeper
> cluster effectively continues from where the pre cluster left off?  Am I
> missing something?
>
> --
Ted Dunning, CTO
DeepDyve

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