Re: [gentoo-user] switch from gnome/systemd to xfce/openrc borked my system

[Rich Freeman <rich0@gentoo.org>]

On Mon, Aug 19, 2019 at 10:42 AM Raffaele Belardi
<raffaele.belardi@st.com> wrote:
>
> Rich Freeman wrote:
> > Next time you do something like this, keep in mind that Gnome and xfce
> > can co-exist on the same system, and so can openrc and systemd.
>
> Good point, I did not know, in particular for the init systems I thought it was exactly
> the opposite.
>

The only area of incompatibility I'm aware of are the
sysvinit-compatibility links.  Both sysvinit and systemd provide
implementations of common utilities like poweroff, halt, reboot,
telinit, and so on.  There is also init itself.

The versions that come with sysvinit are compatible with both sysvinit
and systemd.  If you don't have sysvinit then systemd can supply
these.  Systemd itself doesn't require these utilities but they are
useful both for compatibility and convenience.  (ie "systemctl
poweroff" works fine, as does sending the command via dbus, but
scripts or sysadmins might prefer to be able to just run "poweroff").
The versions of these supplied by systemd are not compatible with
sysvinit.

A USE flag toggles whether systemd installs these utilities.  If it
does then it blocks sysvinit.  So, you just have to switch that USE
flag to install the two in parallel.  If you don't have systemd
install "init" then you do need to have a kernel command line to
launch systemd directly as init.

Offhand I think that is really the only conflict between the two.
Systemd doesn't use anything but those compatibility utils from
sysvinit but it doesn't mind them being around, and nothing in
sysvinit/openrc should even notice that systemd is installed.

As long as you set the USE flag appropriately you can dual-boot
between the two very easily.  The only gotcha is keeping all your
configs up-to-date as openrc and systemd store things in different
places.  When you install systemd it takes a snapshot of many of your
openrc settings but that is a one-time operation.  Some of those
settings are hard to change if systemd isn't running as PID 1 - I
think the wiki has instructions for how to do this.

--
Rich