[one-users] Instance migration based on resources

[Simon Boulet]

It's definitively possible to do offline upgrade/downgrade with OpenNebula.
You need to cancel the VM and submit a new template reusing the image. The
main problem is the image, you need to make it persistent.

Making hot upgrade/downgrade of CPU and memory is not currently possible
directly in OpenNebula (you have to cheat by doing the changes manually on
the hypervisor, most hypervisors support hot plugging CPU and memory).
Adding that feature in OpenNebula would require quite a bit of work,
notably with the quota feature, perhaps to the scheduler too (migrate if
you try to hotplug more CPU or memory than the host has available), and
also for people using the OpenNebula template description to
do resource based billing. Currently the template is static and never
change. You simply have to parse the template the first time and then look
at the VM history records to properly bill your user. Making the template
attributes change would probably require some resources history records
(knowing at what time the VM resources changed and bill the user
accordingly).

I'm not saying it's not something possible, only that it may be more work
that a lot of us think.

If you have your image set up properly, you can do offline
upgrade/downgrade with OpenNebula with minimal downtime for the VM.

Perhaps a page on the OpenNebula documentation could be created to explain
the situation and show how to do offline upgrade/downgrade with OpenNebula.

Simon



On Wed, Jan 16, 2013 at 10:35 AM, christopher barry <cbarry at rjmetrics.com>wrote:

> On Tue, 2013-01-15 at 23:27 +0000, André Monteiro wrote:
> > Hi Gandalf,
> >
> >
> > If you don't want to destroy the VM for some reason, check my message
> > on
> >
> http://lists.opennebula.org/pipermail/users-opennebula.org/2012-August/020021.html
> >
> >
> > --
> > André Monteiro
> >
>
> reading that thread it appears it was evaluated to potentially be a
> feature (cold update). Did it not get implemented yet? Ideally, hot
> update would be the thing to have. Isn't hotplug cpu and memory
> supported in kvm now?
>
> -C
>
>
>
> _______________________________________________
> Users mailing list
> Users at lists.opennebula.org
> http://lists.opennebula.org/listinfo.cgi/users-opennebula.org
>
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