[systemd-devel] Supporting ExecStartPre= and friends in `systemctl set-property` or `systemd-run -p`

Ivan Shapovalov intelfx100 at gmail.com
Tue May 5 19:52:18 PDT 2015

On 2015-04-24 at 11:10 +0200, Lennart Poettering wrote:
> On Fri, 24.04.15 04:07, Ivan Shapovalov (intelfx100 at gmail.com) wrote:
> > - do `systemd-run` twice and somehow set up the dependencies 
> > between
> >   two transient units
> I'd be happy to take a patch that allows configuring deps for
> transient units when constructing them.

Hi Lennart,

I've just done this (also added manager-side support for
JoinsNamespaceOf= and RequiresMountsFor=, while at it). However, this
turned out to be insufficient for my usecase.

I have to start two transient services, say, A.service and B.service,

- B.service "needs" A.service
  (i. e. B.service Requires=A.service and After=A.service)

- A.service must be stopped as soon as B.service exits
  (i. e. A.service BindsTo=B.service)

And there is a contradiction: I can't make a dependency on an
inexistent unit.
If I create A.service before B.service, I can't set BindsTo=, and if I
create B.service before A.service, I can't set Requires= and After=.

Locally, I've solved this by allowing inverse dependencies to be set
over the bus. That is, I make B.service BoundBy=A.service. Is this
acceptable for upstream?

Ivan Shapovalov / intelfx /
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