On Fri, 4 Aug 2023 08:43:24 +0000
Manfred Wassmann via Dng <dng@???> wrote:

> On Fri, Aug 4, 2023 at 7:19 AM Martin Steigerwald <martin@???>
> wrote:
>
> > Lorenz via Dng - 04.08.23, 00:02:21 CEST:
> > > systemd maintains a compatibility layer with sysvinit, via the initctl
> > > pipe, so when you switch from sysv ---> systemd or vice versa you can
> > > expect shutdown or reboot commands to work as intended;
> >
>
> That's something I referred to in another post WRT this topic. Also I
> pointed out the shutdown problem is the worst case and I showed how to
> resolve it by mounting r/o. Anyways, from a distribution dedicated to init
> freedom I'd expect some sort of a framework which facilitates replacing the
> running init package without getting stuck, so no surprise here.
>
>
> >
> > Didn't have time to catch up with your discussion.
> >
> > But regarding any compatibility layers: I wonder whether that one is
> > under ABI/API stability guarantee. If not, whenever systemd developers
> > feel like it, it could be gone.
> >
> > Maybe it is part of their stability guarantee. But I do not even know
> > how to look this up anymore or whether I am making something up here. I
> > thought they had such a guarantee for parts of systemd.
> >
>
> From my experience, I gave it a try in Debian Bullseye and i ended up with
> a running but removed pid 1 systemd which wasn't able to do anything and
> after trying all other options the system had to be shut down by unplugging
> the power supply. So they may not have a compatibility layer in Debian,
> which seems likely to me, or there is no (functional) stability guarantee
> with systemd.

Hi,
in bookworm you cannot remove systemd even if you try very hard
with dpkg --force-all etc. unless you delete it by hand.
You can install another init with systemd running and reboot to it.
OTOH you can remove sysvinit with dpkg more easily and end
with a removed pid 1. Tested.

Ciao,
Tito