[systemd-devel] Semantic of WantedBy=default.target

[Michal Sekletar]

On Wed, Aug 13, 2025 at 8:22 AM Andrei Borzenkov <arvidjaar at gmail.com>
wrote:

> On Tue, Aug 12, 2025 at 11:59 AM Silvio Knizek <killermoehre at gmx.net>
> wrote:
> >
> > Am Dienstag, dem 12.08.2025 um 11:02 +0300 schrieb Andrei Borzenkov:
> >
> > I spent some time trying to understand why a service that should have
> been started was not. It turned out rather simple - the service was
> WantedBy=default.target, I explicitly used "3" on the kernel command line
> and this made systemd to ignore /etc/systemd/system/default.target.wants.
> >
> > Is there any reason to not treat systemd.unit as default in this case?
> After all, "default target" is the target that systemd starts when running
> as /sbin/init and passing systemd.unit is entirely equivalent to overriding
> default.target once at run-time.
> >
> > Hi Andrei,
> >
> > 3 on the k-c-l means "isolate into multi-user.target", not "make the
> multi-user.target the default.target" or "isolate into default.target".
> >
> > So your default.target was never started.
> >
>
> Sigh. Please explain the reason why starting multi-user.target as
> alias to defaut.target should start different services compared to
> starting multi-user.target as systemd.target on the kernel command
> line.


> I know how it is implemented and why it happens. I ask whether this
> behavior is intentional and reasonable.
>

Hi Andrei,

I don't find current behavior reasonable. Whether it is intentional or not
I do not know, but I don't think so.

In any case, I have seen people using (and expecting)
WantedBy=default.target to mean "please attempt to start this unit in any
default target". Using 3 on kernel cmdline is setting default target for
current boot (from user PoV), and hence unit should be started in my
opinion.

Michal


> > If you want default behaviour, don't specify anything.
> >
> > BR
> > Silvio
>
>
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