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Bug 1990802

Summary:	[OSP 16.2] [Docs] Declare the deprecation of 'qxl' video model
Product:	Red Hat OpenStack	Reporter:	Kashyap Chamarthy <kchamart>
Component:	documentation	Assignee:	Irina <igallagh>
Status:	CLOSED CURRENTRELEASE	QA Contact:	RHOS Documentation Team <rhos-docs>
Severity:	high	Docs Contact:
Priority:	unspecified
Version:	16.2 (Train)	CC:	igallagh
Target Milestone:	ga	Keywords:	Triaged
Target Release:	16.2 (Train on RHEL 8.4)
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:		Doc Type:	Deprecated Functionality
Doc Text:	In Red Hat Openstack Platform (RHOSP) 16.2, support for the QXL video model is deprecated, due to the removal of support for the Spice graphics software in RHEL 9. This will cause issues for instances that use QXL when migrating from RHEL-8 to RHEL-9. Red Hat recommends using the `virtio` video model for both UEFI and BIOS instances, instead of `qxl`. When creating a new instance from an image, set the video model before launching the new instance: + ---- $ openstack image set --property hw_video_model=virtio <image> ---- + To update the video model for existing instances that use the QXL video model: . Stop the instance. . Snapshot the instance. . Update the image metadata on the instance snapshot image to include the property `hw_video_model=virtio`. . Create a new instance using the instance snapshot. + For more information on supported video models, see https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/16.2/html/creating_and_managing_images/appx-image-config-parameters.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2021-09-17 13:26:31 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description Kashyap Chamarthy 2021-08-06 09:29:32 UTC

Description of problem
----------------------

"QXL" is one of the possible display devices a Nova instance can use.
However, QXL comes bundled with Spice graphics software, which will be
completely removed in RHEL-9. The deprecation of Spice itself was
announced in RHEL-8.3[1].

Note that OSP itself does not support Spice graphics, but only the QXL
video model (which comes with one of Spice libraries) as a possible
option.

This removal of QXL, by consequence of removing Spice, in RHEL-9 has
negative impact on a small portion of OSP guests (using QXL) that are
migrating from RHEL-8 to RHEL-9.

[1] https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/8.3_release_notes/rhel-8-3-0-release#deprecated-functionality_virtualization

What now?
----------

Given the negative impact of QXL removal in RHEL 9, OSP 16.2 needs to
announce the deprecation of 'QXL' video model. And in OSP 17 we can
remove the support for QXL altogether.

Recommended alternative
-----------------------

For both UEFI and BIOS guests, the 'virtio' (using libvirt terminology)
video model is recommended. It's a modern display device designed for
virtual machines. It works as follows:

When using the 'virtio' display device, any Linux guest with kernel
4.4[*] — or a kernel with the Linux 'virtio-gpu' driver backported — can
take full advantage of all 'virtio' device features. In case your guest
kernel does not have the ‘virtio-gpu’ driver, no problem: it will still
have a working display, because the 'virtio' device will gracefully
fallback to VGA compatibility mode.

[*] This means RHEL-7 and newer guests, and other Linux distributions
using 4.x or 55.x long-term kernels.

Comment 1 Kashyap Chamarthy 2021-08-06 09:49:07 UTC

More notes
----------

(a) For _existing_ instances, the manual procedure to update the video
    model is somewhat involved (read: painful).  Roughly:

    (1) Stop the instance

    (2) Snapshot it 

    (3) Update the image metadata on the snapshot image to use 'virtio' 
        display dev.

    (4) Then rebuild the instance using the snapshot


(b) Before launching _new_ OSP instances on RHEL-9:

    Users can configure the 'virtio' device as a property
    (`hw_video_model`) on the template disk image from which you boot
    VMs: 

    $ openstack image set \
        --property hw_video_model=virtio \
        <template_disk_image_UUID>

    And then boot off the 'template_disk_image_UUID'.  

    Or you can directly specify the video model at the time of guest
    creation too ("server create" is just simply creating VM):

    $ openstack server create --flavor m1.micro \
        --image rhel8.4 \
        --property 'hw_video_model=virtio' vm1

Comment 2 Kashyap Chamarthy 2021-08-06 10:01:30 UTC

(In reply to Kashyap Chamarthy from comment #1)

[...]
 
>     Or you can directly specify the video model at the time of guest
>     creation too ("server create" is just simply creating VM):
> 
>     $ openstack server create --flavor m1.micro \
>         --image rhel8.4 \
>         --property 'hw_video_model=virtio' vm1


Please ignore this above command; it is not valid, as flavor extra specs
do not expose video models.  The only valid approach for new instances
is option (a) — updating the image metadata.  

(Thanks to Lee and Stephen on IRC for the correction.)

Comment 10 Irina 2021-09-17 13:26:31 UTC

Updated content available on the Customer Portal:

https://access.redhat.com/documentation/en-us/red_hat_openstack_platform/16.2/html/creating_and_managing_images/appx-image-config-parameters