libvirt-guests configurability regression

[Laszlo Ersek]

Hi,

I'm really unhappy about commit 8eb4461645c5 ("remove sysconfig files",
2022-01-17), first included in release v8.1.0.

The (a) well-documented and (b) easily editable config file
"/etc/sysconfig/libvirt-guests" is now gone. So if I want to do now on
Fedora 36 the same thing that I used to do on up to and including Fedora
35, I now need to consult a new manual page (from grandparent commit
161727417a91, "docs: Add man page for libvirt-guests", 2022-01-17), and
collect a bunch of options manually.

The message on commit 8eb4461645c5 says,

    Remove the sysconfig file and place the current desired default into
    the service file.

which I briefly considered a consolation, figuring I'd just copy the
collected bunch of options (and hopefully their comments!) to the same
place as before, from the "service file" -- "libvirt-guests.service".

However, the actual commit does not live up to its promise; for example,
the important ON_SHUTDOWN knob is only *removed* from the codebase by
the commit; it is not reintroduced anywhere (certainly not in
"libvirt-guests.service"). Well, the manual page, two commits up the
branch, documents it, but that's totally no viable replacement.

As of f8ebb5816350:

> $ git grep -w ON_SHUTDOWN
>
> docs/manpages/libvirt-guests.rst:- ON_SHUTDOWN=suspend
> docs/manpages/libvirt-guests.rst:    time to shutdown. When setting ON_SHUTDOWN=shutdown, you must also set
> docs/manpages/libvirt-guests.rst:  "ON_SHUTDOWN" is set to "shutdown". If Set to 0, guests will be shutdown one
> tools/libvirt-guests.sh.in:ON_SHUTDOWN="suspend"
> tools/libvirt-guests.sh.in:    if [ "x$ON_SHUTDOWN" = xshutdown ]; then
> tools/libvirt-guests.sh.in:        ON_SHUTDOWN="shutdown"

... It seems that "tools/libvirt-guests.sh.in" does have some built-in
defaults (going back as far as to 66823690e469, "Init script for
handling guests on shutdown/boot", 2010-05-21), which I could copy and
modify presumably; however, those defaults still lack the previously
directly adjacent documentation.

Please consider remedying this. Readily editable config files with
documentation and defaults included are very powerful. They are not
suitable for all config formats of course (especially hierarchical ones:
consider the domain XML for example), but for flat or otherwise simply
structured config files, offering that productivity boost to end-users
is a no-brainer, IMO. Please restore it if you can.

Thanks
Laszlo