Check that a site is working

Access needed: Monitoring access; server access for node checks.

1. From outside the server, request a known public page and check its status and expected content.
2. Check certificate validity, redirects, and response time for the public hostname.
3. On the server, use bin/zotonic status to verify the intended node and site states.
4. Check error logs, disk capacity, database availability, and backup age.
5. Use a dedicated account for a safe representative authenticated check when required.
6. Monitor important asynchronous work, such as email and media processing, separately.

Alert on user-visible failure, approaching capacity limits, stale backups, and repeated processing failures. Set thresholds from normal operation and name an owner for each alert; do not create alerts nobody can act on.

A successful HTTP response from a fallback or status page can hide a failed site. Match expected content or a site-specific health response, not just status 200. Keep monitoring credentials out of public check URLs.