https://besterry.com/tags/cron/Recent content in Cron on Besterry — Linux & DevOps NotesHugoen-usSat, 17 Feb 2024 00:00:00 +0000https://besterry.com/posts/systemd-timer-vs-cron/Sat, 17 Feb 2024 00:00:00 +0000https://besterry.com/posts/systemd-timer-vs-cron/<p>Cron has been the standard scheduler on Unix for decades. systemd timers are newer, more powerful, but also more verbose.</p> <h2 id="cron-wins-when">Cron wins when</h2> <p>Cron is perfect for one-line scripts that need to run on a simple schedule. Writing:</p> <pre tabindex="0"><code>0 3 * * * /usr/local/bin/backup.sh </code></pre><p>is fast, requires no other files, and works on every Unix-like system since the 1970s.</p> <h2 id="systemd-timers-win-when">systemd timers win when</h2> <p>You want any of these:</p> <ul> <li>Logging integrated with journalctl</li> <li>Dependencies on other units (<code>After=network-online.target</code>)</li> <li>Resource limits (<code>MemoryMax=</code>, <code>CPUQuota=</code>)</li> <li>Randomized delays to avoid thundering herd (<code>RandomizedDelaySec=</code>)</li> <li>The ability to manually trigger with <code>systemctl start</code></li> <li>Catch-up behavior after system was off (<code>Persistent=true</code>)</li> </ul> <h2 id="minimal-systemd-timer-example">Minimal systemd timer example</h2> <p><code>/etc/systemd/system/backup.service</code>:</p>