Understand whether weston on Wayland can replace Xvfb

[sxa]

CentOS Stream 10 has chosen to remove all support for xorg and that includes xvfb.
weston is a potential alternative, but while it's available in EPEL10 it does not install properly due to broken dependencies.

Assuming this is the first notable distribution to have dropped all the xorg packages, and they won't add it back in, we should investigate alternatives in order to be able to continue to run the AQA tests that expect a display to be available.

(FYI @judovana in case anyone in your team has already investigated this)

[judovana]

Hi. Thanx for heads up. No, we had not hit it. We do not relay on xvfb. We use full vms which have theirs "normal" display.

[judovana]

@zzambers fyi too.

[sxa]

Hi. Thanx for heads up. No, we had not hit it. We do not relay on xvfb. We use full vms which have theirs "normal" display.

Interesting. So you do have them automatically logging into the UI on boot?

[sxa]

It looks like, if you can install westion (I tried on Ubuntu) then this:

weston --no-config --socket=wayland-vfb --backend=headless-backend.so --xwayland

will start a virtual server. It will display a line like this in the output which will give you the X11 display number:

[11:55:58.278] xserver listening on display :1 

In a container there are a couple of gotchas:

1. You need to create an empty directory, mode 0700 and set XDG_RUNTIME_DIR to it.
2. You need to pre-create /tmp/X11-unix otherwise you get a segmentation fault with --xwayland after this error: failed to bind to /tmp/.X11-unix/X0: No such file or directory

Altref: https://github.com/Xpra-org/xpra 4282 https://unix.stackexchange.com/questions/653672/virtual-wayland-display-server-possible

[sxa]

Trying on fedora 40: Note: xclock -display :0 with weston started on :0 doesn't appear to work:

Error: Can't open display: :0

Even though running weston with a 'real' display as :0 seems ok ...

Problem was xwayland-run not being installed to provide /usr/bin/Xwayland