[systemd-devel] Restarting service starts stopped dependants

[Adam Zegelin]

> On 10 Feb 2015, at 6:46 am, Andrei Borzenkov <arvidjaar at gmail.com> wrote:
> 
> B is started because C is started so it is not relevant.

Yes, this is expected because B is a dependency of C. Starting C should start B.
I mentioned it because, to me, it was unexpected that /re/starting A caused B to start.

> C is started probably due to logic "if A and C are running and you
> restart A you should also restart C". I am not convinced it is the
> right thing to do TBH, but well …

Restarting C as a result of restarting A is correct behaviour to me, but
only if C was already running.

A restart = stop + start in a single transaction, correct?

As such, `systemctl restart A` should:
- Stop A
- Stop C (if it’s running) as C can’t run without A (Requires=A)
- Start A
- Start C, but only if C was previously running.

Starting C only if it was running previously makes sense, because `start` is not
transitive.


> Does patch below help?
> 
> diff --git a/src/core/transaction.c b/src/core/transaction.c
> index b0b3d6b..8901119 100644
> --- a/src/core/transaction.c
> +++ b/src/core/transaction.c
> @@ -1027,7 +1027,7 @@ int transaction_add_job_and_dependencies(
>                 if (type == JOB_STOP || type == JOB_RESTART) {
> 
>                         SET_FOREACH(dep, ret->unit->dependencies[UNIT_REQUIRED_BY], i) {
> -                                r = transaction_add_job_and_dependencies(tr, type, dep, ret, true, override, false, false, ignore_order, e);
> +                                r = transaction_add_job_and_dependencies(tr, type == JOB_RESTART ? JOB_TRY_RESTART : type, dep, ret, true, override, false, false, ignore_order, e);
>                                 if (r < 0) {
>                                         if (r != -EBADR)
>                                                 goto fail;

I will try. I note that TRY_RESTART “… does nothing if units are not running.” (systemctl(1)), which is perhaps the solution to the problem.

Regards,
Adam