Everything in The Nest tagged Reliability.
Renewal is automated almost everywhere and certificates still expire in production. The failure has moved: it is no longer the renewal that breaks, it is everything between the renewal and the socket a browser actually connects to.
A monitoring dashboard has three ways of not knowing something, and every one of them has been drawn as a confident zero at least once. Here is why that is the most expensive bug a status screen can have.
HarpyWatch runs thirty-one distinct kinds of check against a site — not thirty-one variations on an HTTP request. Here is the full list, what each one is actually for, and why they share a single screen.