# systemd units — day/night profile timers

Install per host (adjust names to your unit namespace if not knelperf-):

    install -m 0644 knelperf-dayprofile.service  /etc/systemd/system/
    install -m 0644 knelperf-dayprofile.timer    /etc/systemd/system/
    install -m 0644 knelperf-nightprofile.service /etc/systemd/system/
    install -m 0644 knelperf-nightprofile.timer   /etc/systemd/system/
    systemctl daemon-reload
    systemctl enable --now knelperf-dayprofile.timer knelperf-nightprofile.timer

Design notes (carried from ultix, keep true here):

- `Persistent=true` — a missed flip (host powered off) replays at next boot,
  so the host can never get stuck in the wrong profile across a reboot cycle.
- Services are `Type=oneshot` calling the profile engine with the SAME conf
  file; the conf — not the timer — is the only place values live (fixes the
  ultix wart where the day-flip time was sed-edited on the live timer).
- Day schedule 07:00, night 22:00 local time (batch window 22:00–07:00).
  Change the OnCalendar here when a host needs a different window; the timers
  stay trivial and identical in shape.

Reboot-safety invariant: slice unit files must carry the DAY values as their
static defaults, so an unattended reboot always lands in day mode.