On Fri, Jun 29, 2012 at 4:31 AM, Kok, Auke-jan H <auke-jan.h....@intel.com> wrote: > On Fri, Jun 29, 2012 at 12:49 AM, Nathan <qwerty....@gmail.com> wrote:
>> Looking at the systemd.timer documentation it seems as though all >> the timers are relative. Is there any way to get absolute timers >> relative to real time (cron like functionality - even in a later version?). > > not currently, the timer could should be expanded but it's not that > simple to write something like that consistently. We do not have calendar time event at the moment, because at the time we did all that, we missed the needed kernel pieces. Note, that cron needs to wake up every minute and checks if someone has changed the wall clock, and we did not want to do that. The proper kernel interfaces are there now for timerfd, and a cron-like functionality can be implemented in systemd: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=99ee5315dac6211e972fa3f23bcc9a0343ff58c4 One piece that needs to be sorted out on the systemd side is the notation how to specify the format for specific calendar events, and for re-occuring events, and how and where to store when the last execution happened, to allow cron + anachron + at functionality in one and the same consistent interface. It *may* be some subset or something inspired from rfc2445, but I don't think anybody has really looked into it so far. The current (not really thought out) idea is for systemd to support all the simple cron.daily, cron.weekly, ... things and support that with built-in timers, but leave *all* custom cron jobs and user-cron to the original cron implementation. Which means, that most of the usual systems will not need to install cron/at, but have all the periodic cleanup tasks still hooked up and functional by default. If cron is installed, the service file would check for the existence of a custom cron config file and would start cron only if it needs to run. I short: if you need cron run cron, but if you need only the usual periodic tasks, or just calendar events and don't care about cron configuration files, systemd should do it. Kay _______________________________________________ systemd-devel mailing list systemd-devel@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/systemd-devel