Comment # 11 on bug 1181549 from Bruce Rogers

(In reply to Aleksa Sarai from comment #6)
...
> qemu-system-x86_64:/var/log/lxd/fred-vm/qemu.conf:27: There is no option
> group 'spice'
> qemu-system-x86_64: -readconfig /var/log/lxd/fred-vm/qemu.conf: read config
> /var/log/lxd/fred-vm/qemu.conf: Invalid argument
> : Process exited with a non-zero value
> Try `lxc info --show-log local:fred-vm` for more info
> 
> I have all the relevant SPICE libraries installed so I'll need to look into
> this a little bit more, but my guess is that openSUSE's QEMU is built
> against either an outdated version or has the support disabled for some
> reason.
> 
> [1]: https://www.spice-space.org/download.html

I see that you are grabbing the v5.2 qemu from the Virtualization project.
Here, qemu has further modularized beyond what was in the qemu included in Leap
15.2, which is creating some problems, including with -readconfig file
processing. Someone has reported the error you are hitting, see:
https://bugs.launchpad.net/qemu/+bug/1910696

-readconfig has been de-emphasized for some time, but not yet deprecated. I'm
not sure what the best solution is for what you are trying to do. Can you get
away with using the qemu that ships with Leap 15.2? I don't know anything about
LXD, but is there a way to change how spice is referenced - as in, putting
spice ref's on the qemu command line, and not in a config file, or not use
spice altogether? Is there a way to use LXD in a way that doesn't use qemu's
-readconfig?
You can watch for upstream's handling of this bug for what the approach will be
to deal with this situation.