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Hey,

We did such migration from RDO to the OSA deployment and it was quite
resilient for the end users.
But we've played with LB quite a lot, and had new hardware for net nodes
and control plane, but other then that - it's completely possible to
achieve.

I think as a first step we've spawned new rabbit and mariadb cluster,
though it was easier for us as we ran galera before, so we were able to
just scale up galera cluster and point LB to the new IP. And then it was
just about setup of new services with osa and pointing haproxy to the new
set of the backends. As long as you're deploying the same major version it
should be fine to do so.

When it comes to net nodes, we migrated l3 and DHCP agents to the freshly
provisioned nodes with quite simple script, that list all agents for agent
A, removes agent it from A and adds to B afterwards.

For compute nodes, I think we didn't do even live migrates - just stopped
old service and provisioned new in place. As hostname remains the same, it
was just picked up and placement wasn't complaining. But yeah, live
migration should just work as long as you have same os version.

I think this all should work nicely for kolla as well.

ср, 17 мая 2023 г., 12:12 Ryszard Mielcarek <crazy+kolla at geeks.pl>:

> Dnia 2023-05-17, o godz. 11:53:11
> Piotr Misiak <piotrmisiak1984 at gmail.com> napisał(a):
>
> > Hello,
> >
> > I haven’t done such migration but in theory it should be possible. It
> > depends on how your storage and networking looks like on the current
> > env. Have you thought about creating a new env and migrating workload
> > in stages from the old one to the new one? You can start with a small
> > new env and after freeing compute and storage hardware after first
> > migration you can move them to the new env to make more space for a
> > next migration stage.
>
> Hey Piotr,
> thanks for the idea, but my priority is minimal impact for
> the VMs (I want only live-migrate them during takeover).
> With new env I will end up with downtime for each VM and IP change.
>
> BR,
> crazik
>
> >
> > BR,
> > Piotr
> >
> > On Wed, 17 May 2023 at 11:02 Ryszard Mielcarek <crazy+kolla at geeks.pl>
> > wrote:
> >
> > > Hello,
> > > is there anyone who already did transition on existing cluster,
> > > from package-version to kolla-ansible managed installation?
> > > Looking for guides, tips, your experience on that.
> > >
> > > BR,
> > > crazik
> > >
> > >
>
>
>
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