Upgrading the host

[Erik Skultety]

On Tue, Feb 16, 2021 at 09:51:52AM +0100, Michal Privoznik wrote:
> On 2/12/21 2:10 AM, Marcin Struzak wrote:
> > Hello--
> > 
> > I'm planning on upgrading the OS on my host machine by doing manual
> > re-installation, which will trigger an upgrade of libvirt from 1.1.3 to
> > 6.1.0.  Hardware, storage volumes & paths, etc., will be the same after
> > upgrade.
> > 
> > I was going to redefine & start everything from .xml files, starting
> > with the network
> > 
> >      virsh net-define <network XML>
> >      virsh net-autostart <network>
> >      virsh net-start <network>
> > 
> > and following with all the guests
> > 
> >      virsh define <domain XML>
> >      virsh autostart <domain>
> >      virsh start <domain>
> 
> If you are just upgrading the libvirt package then you do not need to do any
> of this. Libvirt picks everything up after it's restarted. But if you are
> installing host from scratch then ..
> 
> > 
> > I have the following questions:
> > 
> >  1. Do I need to generate XML dumps manually, or is it ok to use the
> >     ones from host's /etc/libvirt?
> 
> .. yes, back up XMls here and use define & start as you suggested.
> 
> >  2. Do I need to define & start storage pools & volumes explicitly, or
> >     will they be picked up from domain definitions?
> 
> Storage pools won't be defined automatically. You need to save their XMLs
> too. You can find them under /etc/libvirt/storage/. Don't forget on secrets
> if you use them too.

Needless to say, if you're backing up /etc/libvirt/<whatever> make sure
libvirtd is down first, so that all the settings are properly dumped by the
daemon to the respective XMLs.

Erik