Re: [Libguestfs] [virt-v2v wave 2 PATCH v1 03/16] output: handle Standard_VGA in the OpenStack format
On Tue, Nov 16, 2021 at 11:31:48AM +0100, Laszlo Ersek wrote:
Hi Kashyap,
Heya,
On 11/15/21 14:54, Kashyap Chamarthy wrote:
[...]
>> diff --git a/output/openstack_image_properties.ml
b/output/openstack_image_properties.ml
>> index 72f3e9d9261d..9d466ecfbf0f 100644
>> --- a/output/openstack_image_properties.ml
>> +++ b/output/openstack_image_properties.ml
>> @@ -43,7 +43,7 @@ let create source inspect { target_buses; guestcaps;
target_firmware } =
>> | RTL8139 -> "rtl8139");
>> "hw_video_model",
>> (match guestcaps.gcaps_video with
>> - | Standard_VGA -> assert false
>> + | Standard_VGA -> "vga"
>> | QXL -> "qxl"
>> | Cirrus -> "cirrus");
>
> Please also add an entry for "bochs" video model.
That is not useful for us in this BZ / patch series. The purpose of
virt-v2v here is that the converted domain start with *some* usable
video device.
Ah, noted.
After discussing the potential options with Gerd at length
(especially based on his blog post), it became clear that VGA was the
best choice -- smaller attack surface than QXL, performance-wise just as
fine for the above-stated virt-v2v purpose, and universally recognized
by all guests we care about. Therefore VGA replaces QXL and also the
older (compat) Cirrus. The whole idea is to simplify / unify as much as
possible.
Understood; and it makes full sense. FWIW, a few months ago I too had a
disucssion with Gerd, based on his famous blog post, to pick a saner
default for OpenStack (it uses the undersirable "cirrus" now). I've
recently filed an RFE[1] to switch to "virtio" as the default, because:
- Any Linux guest with kernel 4.4 (or a kernel with the Linux
'virtio-vgpu' driver backported) can take full advantage of the
'virtio' display device.
- In case your guest kernel does _not_ have the kernel driver (called
"virtio-gpu.ko"), no problem: the 'virtio' display device will
gracefully fallback to VGA compatibility mode.
[1] https://blueprints.launchpad.net/nova/+spec/virtio-as-default-display-device
Adding a mapping for Bochs is not useful here, as virt-v2v will not
intend (in the foreseeable future) to produce such output (= converted)
domains. Once the converted domain lives in OpenStack, the admin can
easily change the video device, but that's beyond virt-v2v's mandate.
>
> With that amended, FWIW:
>
> Reviewed-by: Kashyap Chamarthy <kchamart(a)redhat.com>
So, can I take your R-b only for the correctness of "vga"?
Yes, please - for whatever it's little worth :-)
("Completeness", with regard to Bochs for example, is not a
goal here,
again.)
Yep, understood.
[...]
--
/kashyap