[systemd-devel] Examples to distinguish Before=/After= and Wants=/Requires=/BindsTo=

[Lennart Poettering]

On Fr, 17.09.21 19:04, Kenneth Porter (shiva at sewingwitch.com) wrote:
65;6402;1c
> --On Friday, September 17, 2021 12:49 PM +0200 Lennart Poettering
> <lennart at poettering.net> wrote:
>
> > more specific example: you can use apache without mysql, and you can
> > use mysql without apache, but quite often they are used together, and
> > if so you likely want to start mysql first, and apache second, since
> > it likely consumes services of mysql, and not the other way
> > round. Hence in this example, you'd place an ordering dep, but not
> > requirement dep.
>
> Would such an ordering dependency without a requirements dependency allow
> apache to start without mysql?

Yes.

> Or does an ordering dependency imply a
> requirements dependency?

No.

> In which case, could systemd automatically infer
> the requirements from the ordering?

No.

Lennart

--
Lennart Poettering, Berlin