How to manage web server failure? [closed]

Is thera a DNS level managment logic like DNS -> IP Server 1 DNS -> IP Server 2 if Server 1 is down ?

What about service workers?, I don't want to filter all traffic trough a service worker, just check a single file, if timeout, just redirect to server 2. And still not fully compatible https://caniuse.com/?search=service%20worker

How web servers failure is supose to be managed?