[systemd-devel] OnCalendar every X minutes

[Mirco Tischler]

2015-03-29 23:48 GMT+02:00 Max <maxim.suraev at campus.tu-berlin.de>:
> 29.03.2015 21:28, T.C. Hollingsworth пишет:
>>
>> On Mar 29, 2015 9:52 AM, "Max" <maxim.suraev at campus.tu-berlin.de
>> <mailto:maxim.suraev at campus.tu-berlin.de>> wrote:
>> >
>> > Hi.
>> >
>> > Is there a way to make timer unit which will execute things every X minutes where X
>> > is not divisor for 60?
>> > In case of divisor it's obvious:
>> >
>> > [Timer]
>> > OnCalendar=*:00/10
>> >
>> > Will run every 10 minutes which nicely fit into 60 minutes hour. What if I would like
>> > to run things every 11 minutes: 0, 11, 22, 33, 44, 55, 66, 77...
>> >
>> > If I interpret http://www.freedesktop.org/software/systemd/man/systemd.time.html
>> > correctly than
>> > OnCalendar=*:00/11 will run on 0, 11...44,55,0,11... resulting in unevenness at the
>> > end of an hour.
>> >
>> > Am I missing something?
>>
>> Yes. :-)  See OnActiveSec and related options, listed right above OnCalendar in the
>> documentation you linked to.
>>
>
> You probably mean http://www.freedesktop.org/software/systemd/man/systemd.timer.html
> which is indeed easy to confuse with what I've linked too :)
>
> Unfortunately it doesn't have any examples :(
>
> [Timer]
> OnActiveSec=11min
>
> Will this fire up once after the timer activation? How do I combine it with other
> directives to make it fire _every_ 11 minutes?
>
> cheers,
> Max.
>
What you want is OnUnitActiveSec=11min. This will cause the service
(or type of unit) associated with the timer unit to start every 11
minutes. But only if the service isn't still activated as I
understand.
OnActiveSec=11min will start the service once 11 minutes after the
timer unit itself is started.
There's also OnUnitInactiveSec where the service is started 11 minutes
after it has stopped. This may be useful if your service may need more
than 11 minutes until it exits.

In the man page it is recommended to combine OnUnitActiveSec with
onBootSec to start the service once after boot and in regular
intervals from then on.

However there's one difference between these relative triggers and
OnCalendar: you can only use Persistent= in combination with
OnCalendar. This means that if your timer elapses in 5 minutes and you
suspend your machine for an hour or so, after resume it still elapses
in 5 minutes.

Mirco