Open Stack

Yes, I am fully aware of support implications if you edit this.  But
fortunately this is not in any way a vendor support OpenStack deployment

On Fri, Oct 30, 2020 at 1:29 PM Sean Mooney <smooney at redhat.com> wrote:

> On Fri, 2020-10-30 at 17:23 +0000, Stephen Finucane wrote:
> > On Fri, 2020-10-30 at 11:56 -0500, vladimir franciz blando wrote:
> > > Hi,
> > > I edited the  libvirt xml (virsh edit...) file of a running Windows
> > > server instance because I changed the video model type from cirrus to
> > > vmvga so it can support a higher resolution on a console (cirrus
> > > supports up to 1280 only).
> > > After editing, i "soft-rebooted" the instance and the new
> > > configuration sticks.  That's awesome.
> >
> > Please don't do this :) You shouldn't change things about an instance
> > behind nova's back. It breaks resource tracking and can cause all sorts
> > of horribleness.
>
> if you have support form an openstack vendor like redhat editing the domain
> xml also make that vm unsupported until its restroed to the way nova
> generated.
> it might also make other issue caused as a resulted unsupported.
> so unless you are self supporting you cloud be very carful with doing this.
> >
> > > But when you do a "hard-reboot" it will revert back to the original
> > > config.
> >
> > Hard reboot builds configuration from scratch, dumping the existing
> > XML. This is built from the same things used when you first create the
> > instance (flavor + extra specs, image + metadata, host-level config,
> > ...).
> >
> > What you want is the 'hw_video_model' image metadata property. Set this
> > and rebuild your instance:
> >
> >         openstack image set --property hw_video_model=vmvga $IMAGE
> this is the supported way to change this value ^
> it will take effect for new instances.
> >         openstack server rebuild $SERVER $IMAGE
> and this is the only supported api action that can also change this value.
> however i dont think rebuilding to the same image will update the image
> metadata.
> you currenlty need to rebuild to a new image. this is due to an
> optiomisation we
> have to avoid needing to go to the scheuler if we use the same image.
>
> the unsupported way to change this without rebuilding the instance is to
> add
> img_hw_video_model=vmvga to the system metadata table for that instance.
>
> if your cloud is supported by a vendor this will also invalidate your
> suport
> in all likely hood as db modificaiton generally are unsupported without an
> exception.
> if you can rebuild the guest that is the best approch but it wont work for
> boot form volume
> instances and it willl destory all data in the root disk of all other
> instances.
>
> >
> > Note that rebuild is a destructive operation so be sure you're aware of
> > what this is doing before you do it.
> >
> > Stephen
> >
> > > I also tried to do a "shut-down" then "start" again, but it still
> > > reads the original config.  Not sure where it  is reading the config
> > > from...
> > >
> > > Regards
> > > Vlad
> >
> >
>
>
>
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