scheduling

name	scheduling
description	This skill should be used when the user asks to "schedule daily restic backups", "create a systemd timer for restic", "set up a cron job for backups", "run my backup at a specific time/timezone", or needs a timezone-aware schedule (systemd timer, or cron fallback on non-systemd hosts).

Scheduling restic Backups

Run the backup script daily, on time, in the right timezone. Prefer a systemd timer (timezone-aware, handles missed runs, integrates with OnFailure= alerting). Use cron only on non-systemd hosts. Ready-to-paste units are in references/systemd-units.md.

Do not enable the schedule until verify-backup passes (first run + check + test-restore). Install the units now, enable them later.

systemd timer (preferred)

Two units in /etc/systemd/system/:

restic-backup.service (oneshot, niced so it doesn't starve the host):

[Unit]
Description=restic backup to object storage (encrypted)
Wants=network-online.target
After=network-online.target docker.service

[Service]
Type=oneshot
Nice=10
IOSchedulingClass=idle
ExecStart=/usr/local/sbin/restic-backup.sh
TimeoutStartSec=6h

restic-backup.timer:

[Unit]
Description=Daily restic backup

[Timer]
OnCalendar=*-*-* 03:00:00
Persistent=true
RandomizedDelaySec=1800

[Install]
WantedBy=timers.target

Reload and verify the calendar resolves before enabling:

systemctl daemon-reload
systemd-analyze calendar "*-*-* 03:00:00" --iterations=3   # prints the next 3 run times

Timezone

systemd OnCalendar uses the server's local time by default — set the server timezone with timedatectl set-timezone Europe/Kyiv, or pin it per-timer (systemd ≥ 252):

[Timer]
OnCalendar=*-*-* 03:00:00
Timezone=Europe/Kyiv

systemd-analyze calendar "*-*-* 03:00:00 Europe/Kyiv" checks a zoned expression. Persistent=true runs a missed backup after downtime; RandomizedDelaySec spreads load and avoids hammering R2 at exactly the same second.

cron fallback (non-systemd hosts)

/etc/cron.d/restic-backup — set the timezone and prevent overlapping runs with flock:

CRON_TZ=Europe/Kyiv
0 3 * * * root /usr/bin/flock -n /var/run/restic-backup.lock /usr/local/sbin/restic-backup.sh

CRON_TZ makes the schedule timezone-aware. flock -n ensures a long backup never overlaps the next run. cron's PATH is minimal — the script sets its own absolute PATH (see backup-script).

Enable (only after verification)

systemctl enable --now restic-backup.timer
systemctl list-timers restic-backup.timer   # shows NEXT run time

Gotchas

• Enable only after verify-backup — never schedule an unverified backup.
• daemon-reload after editing units, or systemd runs the old definition.
• Persistent=true catches runs missed while the host was off.
• Avoid concurrent runs on one repo — flock for cron; systemd oneshot won't overlap itself, but watch out for a manual run colliding with the timer (causes a repo lock → see troubleshoot).
• Timezone source — system tz vs per-timer Timezone= vs cron CRON_TZ; pick one and verify with systemd-analyze calendar.
• Schedule the periodic check (from monitoring) off the backup hour to avoid repo-lock contention.

What this skill does NOT cover

• The script itself → backup-script
• First run + enabling gate → verify-backup
• Failure alerts / OnFailure= wiring → monitoring