[systemd-devel] systemctl start second.service first.service

[Uoti Urpala]

On Thu, 2018-01-11 at 10:59 +0000, 林自均 wrote:
> I have 2 service unist: first.service and second.service. I
> configured "After=first.service" in second.service. Both services are
> "Type=oneshot".
> 
> If I execute:
> 
> # systemctl start first.service second.service
> 
> The ordering dependency will work, i.e. second.service will start
> after first.service.
> 
> However, if I execute:
> 
> # systemctl start second.service first.service
> 
> first.service and second.service will start at the same time.
> 
> Is this behavior documented somewhere? Thanks!

I'd guess this is due to systemctl starting each listed unit
independently rather than as a single transaction. Thus, the second
version first starts second.service without first.service being active
at all. Since there's only an After relationship, not Wants/Requires,
second.service will immediately start. Then systemctl starts
first.service; since second.service is already running, there's nothing
the After relationship could affect.