How to automatically change ip in A DNS records when it is unavailable?

Question

Domain Name System

Hello. There is a domain on reg.ru. There is a server behind the router with ip1 (everything works, everything is fine) and this ip1 is in the A record on the domain. Suppose the channel to ip1 falls and in this case there is a backup channel of another provider. But at the backup provider, of course, I have ip2 on the external side and, accordingly, the domain does not redirect (except perhaps a day after editing zone A). We need some kind of service like DNS, so that if ip1 is not available, it would redirect to ip2, ip3, etc. ... a la failover dns, super-available and cloudy. Who knows, please advise.

Answer 1

This is called load failover.
All decent dns hostings have them - for example, cloudns, dnsmadeeasy, etc.

Answer 2

https://developers.cloudflare.com/load-balancing/about

Answer 3

https://www.cloudflare.com/ has a load balance.
This is if you need an external service that will balance and monitor itself.