Docker Compose YAML & Linux systemd Service Unit Generator

Cron, systemd Timers & Compose Restarts: Scheduling Without the Syntax Pain

Every developer has stared at "*/15 2 * * 1-5" and tried to remember which field is which. Cron's five fields — minute, hour, day of month, month, day of week — are compact to the point of hostility, and the special strings (@daily, @reboot) only cover the easy cases. The moment you need "every 20 minutes during business hours on weekdays," you are doing mental arithmetic that a generator handles in one click. Getting it right matters enormously: a backup job scheduled with the fields shifted by one position does not run at the wrong time — it runs never, or it runs constantly, and both failures are silent.

systemd timers are cron's modern replacement on most Linux servers, and they trade terseness for readability in the best possible way. Instead of five cryptic fields you write OnCalendar=*-*-* 02:00:00, which practically reads like English, and you gain logging through journalctl, dependency ordering, randomized delays to avoid thundering herds, and "run the missed job at boot" via Persistent=true — capabilities cron simply cannot offer. The catch is the two-file dance: a .timer unit that schedules and a .service unit that executes, and forgetting to enable both is the classic silent failure.

Docker Compose covers the third corner of the scheduling world: keeping containers alive rather than scheduling them. The restart policy choice — no, on-failure, always, unless-stopped — is a real decision with consequences: "always" will resurrect a container even after you deliberately stopped it, which surprises people during maintenance windows. Healthchecks layered on top let Compose restart only genuinely sick containers instead of flapping on slow starts. Pick your scheduler, describe the schedule in plain words, and the generator emits the cron line, the timer/service pair, or the compose snippet with the semantics spelled out beside each field.