[systemd-devel] Special targets - should they Want or be WantedBy?

[Lennart Poettering]

On Sat, 12.03.11 13:00, Andrey Borzenkov (arvidjaar at mail.ru) wrote:

> On Sat, Mar 12, 2011 at 3:14 AM, Michael Biebl <mbiebl at gmail.com> wrote:
> > 2011/3/12 Michael Biebl <mbiebl at gmail.com>:
> >> 2011/3/11 Andrey Borzenkov <arvidjaar at mail.ru>:
> >>> On Fri, Mar 11, 2011 at 9:10 PM, Mike Kazantsev <mk.fraggod at gmail.com> wrote:
> >>
> >>>
> >>>> Btw, rsyslog.service seem to be installed into multi-user.target.wants,
> >>>> why not syslog.target, which seem to indicate the point where proper
> >>>> syslog daemon is running (according to systemd.special(7))?
> >>>>
> >>>
> >>> Actually good question (same as for portmap) - who should pull in
> >>> syslog.target then?
> >>
> >> Yeah, I noticed this myself already. Quite a bit of syslog output
> >> ended up in /proc/kmsg during boot because rsyslog was started rather
> >> late (via multi-user.target).
> >> Afaics, there is not explicit symlink pulling in syslog.target, so I
> >> assume it is handled internally by systemd. Lennart?
> >
> > Turns out, that indeed syslog.target is not automatically started.
> > I symlinked syslog.target into multi-user.target.wants and
> > rsyslog.service into syslog.target.wants.
> >
> > Now all services with After=syslog.target are correctly started after
> > rsyslog.service.
> >
> > Lennart, I think we should add those changes to systemd and rsyslog.service.
> >
> 
> The problem is not limited to syslog and applies to all special
> targets that serve as "virtual provides"
> 
> Actually I think design should be reversed. The service that
> implements this virtual provide (syslog, network, rpcbind, smtp, ...)
> should pull in special target. This way you ensure

Hmm, interesting idea. I wonder though if we might want to go even one
step further: make the .target unit Want the .service unit and vice versa,
too; but order the .target unit after the .service unit.

That way, starting rsyslog.service will pull up syslog.target, but
pulling up the latter will also start rsyslog.service.

I need to think about this...

Lennart

-- 
Lennart Poettering - Red Hat, Inc.