Docs: add the "Viewing cron logs using journalctl" section

templates/docs/monitoring_cron_jobs.html

@@ -79,6 +79,9 @@ Transient error is a timeout or an HTTP 5xx response code.</dd>
 <dd>Redirect curl's stdout to /dev/null (error messages still go to stderr).</dd>
 </dl>
 <h2>Looking up Your Machine's Time Zone</h2>
+<p>If your cron job consistently pings SITE_NAME an hour early or an hour late,
+the likely cause is a timezone mismatch: your machine may be using a different timezone
+than what is configured on SITE_NAME.</p>
 <p>On modern GNU/Linux systems, you can look up the time zone using the
 <code>timedatectl status</code> command and looking for "Time zone" in its output:</p>
 <div class="text highlight"><pre><span></span><code>$ timedatectl status
@@ -90,4 +93,17 @@ Transient error is a timeout or an HTTP 5xx response code.</dd>
 </span>System clock synchronized: yes
               NTP service: active
           RTC in local TZ: no
+</code></pre></div>
+
+
+<h2>Viewing cron logs using <code>journalctl</code></h2>
+<p>On a systemd-based system, you can use the <code>journalctl</code> utility to see system logs,
+including logs from the cron daemon.</p>
+<p>To see live logs:</p>
+<div class="bash highlight"><pre><span></span><code>journalctl -f
+</code></pre></div>
+
+
+<p>To see logs from e.g. the last hour, and only from the cron daemon:</p>
+<div class="bash highlight"><pre><span></span><code>journalctl --since <span class="s2">&quot;1 hour ago&quot;</span> -t CRON
 </code></pre></div>

templates/docs/monitoring_cron_jobs.md

@@ -85,6 +85,10 @@ suit your needs.
 
 ## Looking up Your Machine's Time Zone
 
+If your cron job consistently pings SITE_NAME an hour early or an hour late,
+the likely cause is a timezone mismatch: your machine may be using a different timezone
+than what is configured on SITE_NAME.
+
 On modern GNU/Linux systems, you can look up the time zone using the
 `timedatectl status` command and looking for "Time zone" in its output:
 
@@ -99,3 +103,20 @@ System clock synchronized: yes
               NTP service: active
           RTC in local TZ: no
 ```
+
+## Viewing cron logs using `journalctl`
+
+On a systemd-based system, you can use the `journalctl` utility to see system logs,
+including logs from the cron daemon.
+
+To see live logs:
+
+```bash
+journalctl -f
+```
+
+To see logs from e.g. the last hour, and only from the cron daemon:
+
+```bash
+journalctl --since "1 hour ago" -t CRON
+```