[systemd-devel] Requires and After

[Michael Chapman]

On Wed, 2 Jan 2019, Jérémy Rosen wrote:
> 
> >> What's the benefit of not having After= for those services?
> >    I guess they can start and do their initialization in parallel with
> > the service they require.
> In that case, what is the benefit or Requires vs Wants ?
> 
> I might be missing something about what Requires does (shutdown ?) but at that
> point, Wants would be a better dependency, no ?

If a unit Requires=other.service, any stop or restart job for 
other.service is propagated back to this unit (the latter as try-restart). 
This does not occur with Wants=.

In _most_ cases this back-propagation isn't needed, which is why Wants= is 
generally preferred.