Operating it

Once you understand how it decides, the operating concerns are small and few:

• Running as a daemon: watch-only versus --apply, and what the loop does each round.
• Advisory mode: running it permanently as an adviser that writes its conclusion to a file you paste by hand, and never touches the host.
• Alerting: the metrics that tell you whether it is working, and the one distinction (watching versus acting) that is invisible without them.
• Recovering a host: what happens, and what to do, when php-fpm will not start.