Changes are previewed, validated and reversible
A website change goes through these six steps. Mail, SSH and the firewall are checked the same way, and a firewall change undoes itself unless you confirm it.
Preview. Ask for a dry run and get the per-file diff before anything happens.
Render. The change becomes a new, complete configuration generation beside the live one.
Validate.
nginx -tandphp-fpm -tcheck the exact files that would go live.Swap. One atomic switch makes the new generation live.
Health check. Every changed site is requested through the server's own nginx.
Keep or roll back. Any failure flips back to the previous generation on its own. The last 30 stay available.