If a service failed too often, systemd will not start the service until the failed state is reset.
systemctl reset-failed ceph-mgr@ceph1
https://coreos.com/os/docs/latest/scheduling-tasks-with-systemd-timers.html https://wiki.archlinux.org/index.php/Systemd/Timers
/etc/systemd/system/foo.timer
[Unit]
Description=Run foo weekly
[Timer]
OnCalendar=weekly
Persistent=true
[Install]
WantedBy=timers.target
OnCalendar format
OnCalendar=DayOfWeek Year-Month-Day Hour:Minute:Second
OnCalendar=Mon,Tue *-*-01..04 12:00:00
Test format/date
systemd-analyze calendar "Mon,Tue *-*-01..04 12:00:00"