On 09/06/2018 10:04 AM, Cole Robinson wrote:
On 09/06/2018 09:04 AM, Martin Kletzander wrote:
On Wed, Sep 05, 2018 at 03:37:22PM +0100, Daniel P. Berrangé wrote:
On Wed, Sep 05, 2018 at 02:01:42PM +0200, Martin Kletzander wrote:
On Wed, Sep 05, 2018 at 09:28:52AM +0100, Daniel P. Berrangé wrote:
> On Tue, Sep 04, 2018 at 03:44:12PM -0400, Cole Robinson wrote:
> > Right now in virt-manager we only track a VM's OS name (win10,
fedora28,
> > etc.) during the VM install phase. This piece of data is important
> > post-install though: if the user adds a new disk to the VM
later, we want to
> > be able to ask libosinfo about what devices the installed OS
supports, so we
> > can set optimal defaults, like enabling virtio.
> >
> > There isn't any standard libvirt XML field to track this kind of
info
> > though, so apps have to invent their own schema. nova and rhev
do it
> > indirectly AFAICT. gnome-boxes does it directly with XML like this:
> >
> > <metadata>
> > <boxes:gnome-boxes
xmlns:boxes="https://wiki.gnome.org/Apps/Boxes";>
> > <os-id>http://fedoraproject.org/fedora/28</os-id>
> > ....
> > </boxes:gnome-boxes>
> > </metadata>
> >
> > I want to add something similar to virt-manager but it seems a
shame to
> > invent our own private schema for something that most
non-trivial virt apps
> > will want to know about. I was thinking a schema we could
document with
> > libosinfo, something like
> >
> > <metadata>
> > <libosinfo
> > xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
> > <os-id>http://fedoraproject.org/fedora/28</os-id>
> > </libosinfo>
> > </metadata>
>
> Yes, I would like to see this standardized under <matadata>.
>
Me too and what Cole suggested looks fine.
It occurs to me that we actually need more than just the os-id value.
When you query devices for a given OS, you'll often be told that
multiple
devices are compatible, and the mgmt app can decide which of them to
then
use.
So if we want consistency when later hotplugging, we should make a
record
of which devices we decided to use too, so if the mgmt app changes its
preference, we still know what we originally picked.
eg to express that we use virtio-net and virtio-blk (even if virtio-scsi
was supported by the OS):
<metadata>
<libosinfo
xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
<os id="http://fedoraproject.org/fedora/28"/>
<device id="http://pcisig.com/pci/1af4/1000"/>
<device id="http://pcisig.com/pci/1af4/1001"/>
</libosinfo>
</metadata>
Note, I'm suggesting using an 'id' attribute, rather than naming the
element 'os-id', to be more closely aligned with osinfo schema.
I'm not against that <device id =''/> but it is going to take some
effort to
properly specify what is really meant by that. The fact that some
device model
was chosen for a particular device does not necessarily mean that it is
requested as the default. It only means what is actually encoded in
the XML
already, that is a particular model for a particular device.
Yeah I'm a bit confused by this as well, it's not exactly clear to me
how we would use or set XML like that for virt-manager, and how other
apps would be expected to consume it.
I'll start with the <os id=X/> bit and we can revisit the <device id=X/>
later
Here's the final XML we are setting in virt-manager:
<metadata>
<libosinfo:libosinfo
xmlns:libosinfo="http://libosinfo.org/xmlns/libvirt/domain/1.0";>
<libosinfo:os id="http://fedoraproject.org/fedora/17"/>
</libosinfo:libosinfo>
</metadata>
Only difference is the libosinfo:os bit, vs just 'os'. This matches how
libvirt formats arbitrary metadata XML passed to the DomainSetMetadata
API, and how nova formats its custom metadata
Thanks,
Cole
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