On Tue 29 Apr 2025 at 13:46:18 (-0400), Greg Wooledge wrote:
> On Tue, Apr 29, 2025 at 10:12:10 -0700, Van Snyder wrote:
> > On Tue, 2025-04-29 at 08:03 -0400, Greg Wooledge wrote:
> > > Your run levels are incorrect. "3" included the graphical Display
> > > Manager and "2" did not.
> >
> > Level 0 is shutdown
> > Level 1 is single user
> > Level 2 is multi user
> > Level 3 is multi user with networking
> > Level 4 is not used
> > Level 5 is GUI
> > Level 6 is reboot
>
> OK... it's ugly and horrible and stupidly complicated, and much worse
> than I remembered.
>
> Your list matches
> <https://en.wikipedia.org/wiki/Runlevel#Linux_Standard_Base_specification>
> which shows what LSB defines for runlevels, which I believe is derived
> from Red Hat.
>
> In Debian, before systemd, runlevels 2 through 5 were all identical
> out of the box. You could configure the system's boot behavior by
> changing symlinks on your own system, which would cause runlevels 2-5
> to differ from each other. Or, more commonly, you could simply remove
> whatever packages you didn't want to run.
>
> I could've sworn there was some system I used, at some point in the past,
> where runlevel 2 was without-DM and runlevel 3 was with-DM, but I can't
> remember how long ago that was.
As only runlevels 2&3 gave you VCs on tty2-6, I think it was intended
that you could configure runlevel 3 yourself to do something different
from 2, like starting a DM, and still be able to get back to an unused
VC (VC1 being cluttered up with boot stuff).
I don't remember any changes being made to sysv runlevels when systemd
was introduced, but current sysv users might comment on that.
> Check out some of the other systems shown on that wikipedia page to see
> variants.
>
> In any case, use of the numeric runlevel aliases for systemd targets
> is not the recommended way. Use the actual target names instead, for
> less confusion.
AIUI systemd runs at runlevel 5, which includes graphical.target, even
when you only login at a VC and startx. So it's odd that booting into
runlevel 3 didn't seem to work:
├─────────┼───────────────────┤
│2, 3, 4 │ multi-user.target │
├─────────┼───────────────────┤
│5 │ graphical.target │
├─────────┼───────────────────┤
Is the break in communication between Grub and the kernel, or
the kernel and systemd? I'm not best qualified to answer that,
because my graphical.target.wants includes solely udisks2.service,
and I suspect that I don't even depend on that. Is a DM startup
placed only in graphical.target.wants, and not multi-user.t.w?
Cheers,
David.
