systemd timer fails to start (Invalid argument) when using UTC time

Grisha S asked:

Here is my timer:

Description=Do whatever

OnCalendar=daily UTC


It fails to start with the following error:

Failed to start mytimer.timer: Unit mytimer.timer failed to load: Invalid argument. See system logs and 'systemctl status mytimer.timer' for details.

Sadly systemctl status doesn’t add any clarity to the error message

But, if I remove the UTC literal, it works perfectly:

Description=Do whatever



What am I doing wrong?

This document describes the format accepted by OnCalendar, and it shows that UTC can be used.

Yes, I tried using quotes – doesn’t help. I also tried using the normalized form – same thing


  • OS: CentOS 7
  • kernel: 3.10.0-042stab113.21
  • systemd: systemd-219-19.el7_2.9.x86_64

My answer:

Using OnCalendar= with any timestamp suffixed by UTC requires systemd 228 or later. This functionality was added in systemd 228.

From the systemd changelog:


  • Wherever systemd expects a calendar timestamp specification
    (like in journalctl’s –since= and –until= switches) UTC
    timestamps are now supported. Timestamps suffixed with “UTC”
    are now considered to be in Universal Time Coordinated
    instead of the local timezone. Also, timestamps may now
    optionally be specified with sub-second accuracy. Both of
    these additions also apply to recurring calendar event
    specification, such as OnCalendar= in timer units.

View the full question and any other answers on Server Fault.

Creative Commons License
This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License.