Mark Dain I have a problem at work I'm stuck on and I can't find anything online about this bug. Has anyone ever had a systemd timer configured `OnCalendar=*-*-* 01:30:00` (so 1:30 AM) but it's firing _every 12 hours_?! It runs 1:30 PM too as well as 1:30 AM. Other Linux boxes with "identical, as far as I can tell" configuration behave properly (run once every 24 hours at 1:30 AM). Ubuntu/17.04, Linux/4.9.36, systemd/232. Any tips greatly appreciated, been stuck for days on this! #ComputersAreNotDeterministic

Eric What does it do when it's set to 13:30?

Mark Dain I'll have to check Monday (which may be fine as I rebooted Friday). I'd be completely confused if 13:30 worked as the development server is fine with 1:30... honestly I'd bet a reboot will fix it, and this problem won't ever show up again. If that happens, I guess it can be chalked up to "computers aren't perfect". Bugs exist in systemd, Linux, Xen, and processors themselves

John Olinda One of the most unsettling things about being a sysadmin is how many problems are resolved - sometimes permanently - with a reboot. I can't even begin to remember all the problems that I've never gotten to the bottom of because they popped up once and never again.

Mark Dain This! Yeah, I managed to find the issue - it was another, unrelated service (with another unrelated timer) that was launching it. The unrelated service just had the wrong ExecStart value, and was broken but nobody knew. As for why that never fired on the test server - that particular timer is disabled. The only thing I didn't figure out was why when first installed it would run at 2:30 AM rather than 1:30 AM, but everything has stabilized now.