Open Stack

Ok, thanks a lot
If cold migration is supposed to work between hosts with different
operating systems, we are fine
Cheers, Massimo

On Tue, Dec 6, 2022 at 10:48 AM Sean Mooney <smooney at redhat.com> wrote:

> On Tue, 2022-12-06 at 10:34 +0100, Dmitriy Rabotyagov wrote:
> > Hi Massimo,
> >
> > Assuming you have manual installation (not using any deployment
> > projects), I have several comments on your plan.
> >
> > 1. I've missed when you're going to upgrade Nova/Neutron on computes.
> > As you should not create a gap in OpenStack versions between
> > controllers and computes since nova-scheduler has a requirement on RPC
> > version computes will be using. Or, you must define the rpc version
> > explicitly in config to have older computes (but it's not really a
> > suggested way).
> > 2. Also once you do db sync, your second controller might misbehave
> > (as some fields could be renamed or new tables must be used), so you
> > will need to disable it from accepting requests until syncing
> > openstack version as well. If you're not going to upgrade it until
> > getting first one to Yoga - it should be disabled all the time until
> > you get Y services running on it.
> > 3. It's totally fine to run multi-distro setup. For computes the only
> > thing that can go wrong is live migrations, and that depends on
> > libvirt/qemu versions. I'm not sure if CentOS 8 Stream have compatible
> > version with Ubuntu 22.04 for live migrations to work though, but if
> > you care about them (I guess you do if you want to migrate workloads
> > semalessly) - you'd better check. But my guess would be that CentOS 8
> > Stream should have compatible versions with Ubuntu 20.04 - still needs
> > deeper checking.
> the live migration issue is a know limiation
> basically it wont work across distro today because the qemu emulator path
> is distro specific and we do not pass that back form the destinatino to the
> source so libvirt will try and boot the vm referncign a binary that does
> not exist
> im sure you could propaly solve that with a symlink or similar.
> if you did the next issue you would hit is we dont normally allwo live
> mgration
> form a newer qemu/libvirt verson to an older one
>
> with all that said cold migration shoudl work fine and wihtine any one
> host os live migration
> will work. you could proably use host aggreates or simialr to enforece
> that if needed but
> cold migration is the best way to move the workloads form hypervior hosts
> with different distros.
>
> >
> > вт, 6 дек. 2022 г. в 09:40, Massimo Sgaravatto <
> massimo.sgaravatto at gmail.com>:
> > >
> > > Any comments on these questions ?
> > > Thanks, Massimo
> > >
> > > On Fri, Dec 2, 2022 at 5:02 PM Massimo Sgaravatto <
> massimo.sgaravatto at gmail.com> wrote:
> > > >
> > > > Dear all
> > > >
> > > >
> > > >
> > > > Dear all
> > > >
> > > > We are now running an OpenStack deployment: Yoga on CentOS8Stream.
> > > >
> > > > We are now thinking about a possible migration to Ubuntu for several
> reasons in particular:
> > > >
> > > > a- 5 years support for both the Operating System and OpenStack
> (considering LTS releases)
> > > > b- Possibility do do a clean update between two Ubuntu LTS releases
> > > > c- Easier procedure (also because of b) for fast forward updates
> (this is what we use to do)
> > > >
> > > > Considering the latter item, my understanding is that an update from
> Ubuntu 20.04 Ussuri to Ubuntu 22.04 Yoga could be done in the following
> > > > way (we have two controller nodes and n compute nodes):
> > > >
> > > > - Update of first controller node from Ubuntu 20.04 Ussuri to Ubuntu
> 20.04 Victoria (update OpenStack packages + dbsync)
> > > > - Update of first controller node from Ubuntu 20.04 Victoria to
> Ubuntu 20.04 Wallaby (update OpenStack packages + dbsync)
> > > > - Update of first controller node from Ubuntu 20.04 Wallaby to
> Ubuntu 20.04 Xena (update OpenStack packages + dbsync)
> > > > - Update of first controller node from Ubuntu 20.04 Xena to Ubuntu
> 20.04 Yoga (update OpenStack packages + dbsync)
> > > > - Update of first controller node from Ubuntu 20.04 Yoga to Ubuntu
> 22.04 Yoga (update Ubuntu  packages)
> > > > - Update of second controller node from Ubuntu 20.04 Ussuri to
> Ubuntu 22.04 Yoga (update OpenStack and Ubuntu packages)
> > > > - Update of the compute nodes from Ubuntu 20.04 Ussuri to Ubuntu
> 22.04 Yoga (update OpenStack and Ubuntu packages)
> > > >
> > > >
> > > > We would do the same when migrating from Ubuntu 22.04 Yoga to Ubuntu
> 24.04 and the OpenStack xyz release (where xyz
> > > > is the LTS release used in Ubuntu 24.04)
> > > >
> > > > Is this supposed to work or am I missing something ?
> > > >
> > > > If we decide to migrate to Ubuntu, the first step would be the
> reinstallation with Ubuntu 22.04/Yoga of each node
> > > > currently running CentOS8 stream/Yoga.
> > > > I suppose there are no problems having in the same OpenStack
> installation nodes running the same
> > > > Openstack version but different operating systems, or am I wrong ?
> > > >
> > > > Thanks, Massimo
> > > >
> >
>
>
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