Practical Examples

Learning Focus

This page contains 27 complete examples, each with the .timer unit, the .service unit, activation commands, and expected output. Every example is copy-paste-ready.

How To Use This Page

Examples are grouped by schedule frequency — jump to the pattern you need.
Each example includes systemd-analyze calendar validation where applicable.
Adapt User=, paths, and scripts to your environment.

Every Minute

1. Health Check (Every Minute)

/etc/systemd/system/health-check.service
[Unit]
Description=Lightweight health check

[Service]
Type=oneshot
ExecStart=/usr/local/bin/health-check.sh
StandardOutput=append:/var/log/health-check.log
StandardError=append:/var/log/health-check.log

/etc/systemd/system/health-check.timer
[Unit]
Description=Run health check every minute

[Timer]
OnCalendar=minutely
Persistent=true

[Install]
WantedBy=timers.target

activate.sh
sudo systemctl daemon-reload
sudo systemctl enable --now health-check.timer
systemctl list-timers health-check.timer --no-pager

expected-output.txt
NEXT                        LEFT     LAST                        PASSED  UNIT                ACTIVATES
Mon 2026-03-02 00:01:00 UTC 38s left Mon 2026-03-02 00:00:01 UTC 21s ago health-check.timer  health-check.service

Every 5–30 Minutes

2. Disk Monitoring (Every 5 Minutes)

/etc/systemd/system/disk-check.service
[Unit]
Description=Disk usage alert

[Service]
Type=oneshot
ExecStart=/usr/local/bin/disk-alert.sh
StandardOutput=append:/var/log/disk-alert.log
StandardError=append:/var/log/disk-alert.log

/etc/systemd/system/disk-check.timer
[Unit]
Description=Check disk usage every 5 minutes

[Timer]
OnCalendar=*:0/5
Persistent=true

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=3 '*:0/5'

expected-output.txt
    Next elapse: Mon 2026-03-02 00:05:00 UTC
       Iter. #2: Mon 2026-03-02 00:10:00 UTC
       Iter. #3: Mon 2026-03-02 00:15:00 UTC

3. WordPress Cron Runner (Every 15 Minutes)

Replaces the default wp-cron.php page-visit trigger. Requires define('DISABLE_WP_CRON', true); in wp-config.php.

/etc/systemd/system/wp-cron-runner.service
[Unit]
Description=Run due WordPress cron events

[Service]
Type=oneshot
User=www-data
WorkingDirectory=/var/www/html
ExecStart=/usr/local/bin/wp cron event run --due-now --path=/var/www/html
StandardOutput=append:/var/log/wp-cron.log
StandardError=append:/var/log/wp-cron.log

/etc/systemd/system/wp-cron-runner.timer
[Unit]
Description=Trigger WordPress cron events every 15 minutes

[Timer]
OnCalendar=*:0/15
Persistent=true

[Install]
WantedBy=timers.target

4. CDN Sync (Every 30 Minutes)

/etc/systemd/system/cdn-sync.service
[Unit]
Description=Sync static assets to CDN

[Service]
Type=oneshot
User=www-data
ExecStart=/usr/local/bin/sync-cdn.sh
StandardOutput=append:/var/log/cdn-sync.log

/etc/systemd/system/cdn-sync.timer
[Unit]
Description=Sync CDN every 30 minutes

[Timer]
OnCalendar=*:0/30
Persistent=true

[Install]
WantedBy=timers.target

Hourly

5. Hourly Server Report

/etc/systemd/system/hourly-report.service
[Unit]
Description=Generate hourly server summary

[Service]
Type=oneshot
ExecStart=/usr/local/bin/hourly-report.sh

/etc/systemd/system/hourly-report.timer
[Unit]
Description=Hourly report

[Timer]
OnCalendar=hourly
Persistent=true

[Install]
WantedBy=timers.target

6. Media Sync to Object Storage (Every 2 Hours)

/etc/systemd/system/media-sync.service
[Unit]
Description=Sync uploads to object storage

[Service]
Type=oneshot
User=www-data
ExecStart=/usr/local/bin/rclone sync /var/www/html/wp-content/uploads remote:wp-uploads
StandardOutput=append:/var/log/media-sync.log

/etc/systemd/system/media-sync.timer
[Unit]
Description=Sync media to object storage every 2 hours

[Timer]
OnCalendar=*-*-* 0/2:00:00
Persistent=true

[Install]
WantedBy=timers.target

7. Cache Flush (Every 6 Hours)

/etc/systemd/system/wp-cache-flush.service
[Unit]
Description=Flush WordPress object cache

[Service]
Type=oneshot
User=www-data
WorkingDirectory=/var/www/html
ExecStart=/usr/local/bin/wp cache flush --path=/var/www/html
StandardOutput=append:/var/log/wp-cache-flush.log

/etc/systemd/system/wp-cache-flush.timer
[Unit]
Description=Flush WordPress object cache every 6 hours

[Timer]
OnCalendar=*-*-* 00/6:00:00
Persistent=true

[Install]
WantedBy=timers.target

Daily

8. WordPress Nightly Backup (2:15 AM)

/etc/systemd/system/wp-backup.service
[Unit]
Description=WordPress nightly backup
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
User=www-data
Group=www-data
WorkingDirectory=/var/www/html
ExecStart=/usr/bin/flock -n /var/lock/wp-backup.lock /usr/local/bin/wp-backup.sh
StandardOutput=append:/var/log/wp-backup.log
StandardError=append:/var/log/wp-backup.log
RuntimeMaxSec=2h

/etc/systemd/system/wp-backup.timer
[Unit]
Description=Run WordPress backup nightly at 02:15

[Timer]
OnCalendar=02:15
Persistent=true
RandomizedDelaySec=5m
AccuracySec=1m

[Install]
WantedBy=timers.target

activate.sh
sudo systemctl daemon-reload
sudo systemctl enable --now wp-backup.timer
sudo systemctl start wp-backup.service    # Test run immediately
journalctl -u wp-backup.service -n 20 --no-pager

expected-output.txt
Mar 02 02:15:07 vps wp-backup.sh[1201]: [2026-03-02T02:15:07] Backup started
Mar 02 02:15:42 vps wp-backup.sh[1201]: [2026-03-02T02:15:42] Database exported: 145M
Mar 02 02:16:10 vps wp-backup.sh[1201]: [2026-03-02T02:16:10] Archive created: wp-backup-2026-03-02.tar.gz
Mar 02 02:16:10 vps wp-backup.sh[1201]: [2026-03-02T02:16:10] Done.

9. Log Rotation (Midnight)

/etc/systemd/system/force-logrotate.service
[Unit]
Description=Force logrotate run

[Service]
Type=oneshot
ExecStart=/usr/sbin/logrotate /etc/logrotate.conf

/etc/systemd/system/force-logrotate.timer
[Unit]
Description=Force logrotate daily at midnight

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target

10. Uptime Check (Twice Daily — 9 AM and 9 PM)

/etc/systemd/system/uptime-check.timer
[Unit]
Description=Uptime check twice daily

[Timer]
OnCalendar=09,21:00
Persistent=true

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=4 '09,21:00'

expected-output.txt
    Next elapse: Mon 2026-03-02 09:00:00 UTC
       Iter. #2: Mon 2026-03-02 21:00:00 UTC
       Iter. #3: Tue 2026-03-03 09:00:00 UTC
       Iter. #4: Tue 2026-03-03 21:00:00 UTC

11. Database Export (Daily at 2:30 AM with Lock)

/etc/systemd/system/wp-db-backup.service
[Unit]
Description=WordPress database export

[Service]
Type=oneshot
User=www-data
ExecStart=/usr/bin/flock -n /var/lock/wp-db-backup.lock /usr/local/bin/wp db export /mnt/backups/wp-db.sql --path=/var/www/html
RuntimeMaxSec=1h
StandardOutput=append:/var/log/wp-db-backup.log
StandardError=append:/var/log/wp-db-backup.log

/etc/systemd/system/wp-db-backup.timer
[Unit]
Description=WordPress DB export daily at 02:30

[Timer]
OnCalendar=02:30
Persistent=true
RandomizedDelaySec=5m

[Install]
WantedBy=timers.target

12. Backup Retention Purge (Daily at 4 AM)

/etc/systemd/system/backup-prune.service
[Unit]
Description=Prune backup files older than 14 days

[Service]
Type=oneshot
ExecStart=/usr/bin/find /mnt/backups -name "*.sql" -mtime +14 -delete
StandardOutput=append:/var/log/backup-prune.log

/etc/systemd/system/backup-prune.timer
[Unit]
Description=Prune old backups daily at 04:00

[Timer]
OnCalendar=04:00
Persistent=true

[Install]
WantedBy=timers.target

13. Peak-Hours Cache Warming (8 AM – 8 PM, Every 10 Minutes)

/etc/systemd/system/cache-warm.service
[Unit]
Description=Warm WordPress page cache

[Service]
Type=oneshot
User=www-data
ExecStart=/usr/local/bin/cache-warm.sh

/etc/systemd/system/cache-warm.timer
[Unit]
Description=Warm cache every 10 minutes during peak hours

[Timer]
OnCalendar=*-*-* 08..20:0/10
Persistent=false

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=5 '*-*-* 08..20:0/10'

expected-output.txt
    Next elapse: Mon 2026-03-02 08:00:00 UTC
       Iter. #2: Mon 2026-03-02 08:10:00 UTC
       Iter. #3: Mon 2026-03-02 08:20:00 UTC
       Iter. #4: Mon 2026-03-02 08:30:00 UTC
       Iter. #5: Mon 2026-03-02 08:40:00 UTC

14. SSL Certificate Renewal (Daily 3 AM with Fleet Jitter)

/etc/systemd/system/certbot-renew.service
[Unit]
Description=Renew TLS certificates with Certbot

[Service]
Type=oneshot
ExecStart=/usr/bin/certbot renew --quiet --deploy-hook "systemctl reload nginx"
StandardOutput=append:/var/log/certbot.log
StandardError=append:/var/log/certbot.log

/etc/systemd/system/certbot-renew.timer
[Unit]
Description=Daily certbot renewal with stable fleet jitter

[Timer]
OnCalendar=03:00
Persistent=true
RandomizedDelaySec=30m
FixedRandomDelay=true
AccuracySec=1m

[Install]
WantedBy=timers.target

Certbot only renews if expiry is within 30 days. The --deploy-hook reloads Nginx only when a renewal happens.

Weekly

15. Business Digest (Weekdays at 6 AM)

/etc/systemd/system/daily-digest.service
[Unit]
Description=Send daily business digest

[Service]
Type=oneshot
ExecStart=/usr/local/bin/send-digest.sh

/etc/systemd/system/daily-digest.timer
[Unit]
Description=Business digest on weekdays at 6 AM

[Timer]
OnCalendar=Mon..Fri 06:00
Persistent=true

[Install]
WantedBy=timers.target

16. Weekly WordPress Cleanup (Monday 3 AM)

/etc/systemd/system/weekly-cleanup.service
[Unit]
Description=Weekly WordPress cleanup and optimization

[Service]
Type=oneshot
User=www-data
ExecStart=/usr/local/bin/wp-weekly-cleanup.sh
StandardOutput=append:/var/log/weekly-cleanup.log

/etc/systemd/system/weekly-cleanup.timer
[Unit]
Description=Weekly cleanup every Monday at 03:00

[Timer]
OnCalendar=Mon 03:00
Persistent=true
RandomizedDelaySec=10m

[Install]
WantedBy=timers.target

Use case: wp db optimize, delete old revisions, clear transients.

17. Saturday Maintenance Window (2 AM)

/etc/systemd/system/maintenance.service
[Unit]
Description=Weekly maintenance (heavier tasks)

[Service]
Type=oneshot
ExecStart=/usr/local/bin/maintenance.sh
RuntimeMaxSec=3h
StandardOutput=append:/var/log/maintenance.log

/etc/systemd/system/maintenance.timer
[Unit]
Description=Run heavy maintenance on Saturday at 02:00

[Timer]
OnCalendar=Sat 02:00
Persistent=true
RandomizedDelaySec=15m

[Install]
WantedBy=timers.target

Use case: Full backup, database vacuum, PHP-FPM restart, plugin update dry-run.

Monthly and Beyond

18. Bimonthly Report (1st and 15th at 4 AM)

/etc/systemd/system/bimonthly-report.timer
[Unit]
Description=Bimonthly report on 1st and 15th

[Timer]
OnCalendar=*-*-01,15 04:00:00
Persistent=true

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=4 '*-*-01,15 04:00:00'

expected-output.txt
    Next elapse: Sun 2026-03-15 04:00:00 UTC
       Iter. #2: Wed 2026-04-01 04:00:00 UTC
       Iter. #3: Wed 2026-04-15 04:00:00 UTC
       Iter. #4: Fri 2026-05-01 04:00:00 UTC

19. Monthly Report (1st of Month)

/etc/systemd/system/monthly-report.timer
[Unit]
Description=Monthly server report

[Timer]
OnCalendar=monthly
Persistent=true

[Install]
WantedBy=timers.target

20. Quarterly Billing Export

/etc/systemd/system/quarterly-export.timer
[Unit]
Description=Quarterly billing data export

[Timer]
OnCalendar=quarterly
Persistent=true

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=4 'quarterly'

expected-output.txt
    Next elapse: Wed 2026-04-01 00:00:00 UTC
       Iter. #2: Wed 2026-07-01 00:00:00 UTC
       Iter. #3: Thu 2026-10-01 00:00:00 UTC
       Iter. #4: Fri 2027-01-01 00:00:00 UTC

21. Last Day of Every Month

/etc/systemd/system/month-end-rollup.timer
[Unit]
Description=Month-end data rollup

[Timer]
OnCalendar=*-*~1 00:00:00
Persistent=true

[Install]
WantedBy=timers.target

validate.sh
systemd-analyze calendar --iterations=3 '*-*~1 00:00:00'

expected-output.txt
    Next elapse: Tue 2026-03-31 00:00:00 UTC
       Iter. #2: Thu 2026-04-30 00:00:00 UTC
       Iter. #3: Sun 2026-05-31 00:00:00 UTC

22. First Monday of Each Month

/etc/systemd/system/monthly-first-monday.timer
[Unit]
Description=First Monday of each month at 03:00

[Timer]
OnCalendar=Mon *-*-1..7 03:00:00
Persistent=true

[Install]
WantedBy=timers.target

23. Annual Cleanup (January 1)

/etc/systemd/system/annual-cleanup.timer
[Unit]
Description=Annual cleanup on January 1

[Timer]
OnCalendar=yearly
Persistent=true

[Install]
WantedBy=timers.target

Boot and Monotonic

24. Post-Boot Startup Task (2 Minutes After Boot)

/etc/systemd/system/startup-task.service
[Unit]
Description=One-time startup initialization task

[Service]
Type=oneshot
ExecStart=/usr/local/bin/post-boot-setup.sh
RemainAfterExit=yes

/etc/systemd/system/startup-task.timer
[Unit]
Description=Run startup task 2 minutes after boot

[Timer]
OnBootSec=2min

[Install]
WantedBy=timers.target

25. Boot Then Recurring Hourly (Heartbeat)

/etc/systemd/system/heartbeat.timer
[Unit]
Description=Run heartbeat 30s after boot, then every hour

[Timer]
OnBootSec=30s
OnUnitActiveSec=1h

[Install]
WantedBy=timers.target

26. Cooldown Retry (20 Minutes After Completion)

/etc/systemd/system/retry-worker.timer
[Unit]
Description=Retry worker 20 minutes after each run completes

[Timer]
OnUnitInactiveSec=20m

[Install]
WantedBy=timers.target

"Next run starts 20 minutes after the previous run finished, not 20 minutes after it started."

Advanced

27. User-Level Timer (No Root Required)

~/.config/systemd/user/personal-backup.service
[Unit]
Description=Personal file backup

[Service]
Type=oneshot
ExecStart=%h/bin/backup-home.sh
StandardOutput=append:%h/logs/backup.log

~/.config/systemd/user/personal-backup.timer
[Unit]
Description=Personal backup every 6 hours

[Timer]
OnCalendar=*-*-* 00/6:00:00
Persistent=true

[Install]
WantedBy=default.target

activate-user-timer.sh
systemctl --user daemon-reload
systemctl --user enable --now personal-backup.timer
sudo loginctl enable-linger "$USER"
systemctl --user list-timers --no-pager

Example Quick Reference

#	Pattern	Schedule	Key Feature
1	Health check	`minutely`	High-frequency polling
2	Disk alert	`*:0/5`	Step-based interval
3	WP cron	`*:0/15`	Replaces wp-cron.php
4	CDN sync	`*:0/30`	Periodic sync
5	Hourly report	`hourly`	Keyword shortcut
6	Media sync	`0/2:00:00`	Multi-hour interval
7	Cache flush	`00/6:00:00`	4x daily
8	WP backup	`02:15`	flock + RuntimeMaxSec
9	Log rotation	`daily`	Keyword shortcut
10	Uptime check	`09,21:00`	List operator
11	DB export	`02:30`	flock + jitter
12	Backup purge	`04:00`	find + delete retention
13	Cache warming	`08..20:0/10`	Range + step
14	Certbot	`03:00`	FixedRandomDelay fleet
15	Business digest	`Mon..Fri 06:00`	Range operator
16	Weekly cleanup	`Mon 03:00`	WP optimize
17	Maintenance	`Sat 02:00`	Heavy weekend window
18	Bimonthly	`--01,15 04:00`	Day list
19	Monthly report	`monthly`	Keyword
20	Quarterly	`quarterly`	Keyword
21	Month-end	`-~1 00:00`	Tilde (last day)
22	First Monday	`Mon --1..7 03:00`	Range + day-of-week
23	Annual	`yearly`	Keyword
24	Post-boot	`OnBootSec=2min`	One-shot startup
25	Boot+recurring	`OnBootSec=30s` + `OnUnitActiveSec=1h`	Combined
26	Cooldown retry	`OnUnitInactiveSec=20m`	Gap after completion
27	User timer	`00/6:00:00` + linger	No root, `%h` specifier

What's Next

Production Patterns — hardening, flock overlap prevention, Persistent, jitter, and fleet safety.

Every Minute​

1. Health Check (Every Minute)​

Every 5–30 Minutes​

2. Disk Monitoring (Every 5 Minutes)​

3. WordPress Cron Runner (Every 15 Minutes)​

4. CDN Sync (Every 30 Minutes)​

Hourly​

5. Hourly Server Report​

6. Media Sync to Object Storage (Every 2 Hours)​

7. Cache Flush (Every 6 Hours)​

Daily​

8. WordPress Nightly Backup (2:15 AM)​

9. Log Rotation (Midnight)​

10. Uptime Check (Twice Daily — 9 AM and 9 PM)​

11. Database Export (Daily at 2:30 AM with Lock)​

12. Backup Retention Purge (Daily at 4 AM)​

13. Peak-Hours Cache Warming (8 AM – 8 PM, Every 10 Minutes)​

14. SSL Certificate Renewal (Daily 3 AM with Fleet Jitter)​

Weekly​

15. Business Digest (Weekdays at 6 AM)​

16. Weekly WordPress Cleanup (Monday 3 AM)​

17. Saturday Maintenance Window (2 AM)​

Monthly and Beyond​

18. Bimonthly Report (1st and 15th at 4 AM)​

19. Monthly Report (1st of Month)​

20. Quarterly Billing Export​

21. Last Day of Every Month​

22. First Monday of Each Month​

23. Annual Cleanup (January 1)​

Boot and Monotonic​

24. Post-Boot Startup Task (2 Minutes After Boot)​

25. Boot Then Recurring Hourly (Heartbeat)​

26. Cooldown Retry (20 Minutes After Completion)​

Advanced​

27. User-Level Timer (No Root Required)​

Example Quick Reference​

What's Next​