How to organize automatic switching of the IP to which the domain leads when the server is not working?

Question

Domain Name System

Maybe I worded it incorrectly in the topic, so I'll sign it here.
Now everything is organized:
There are domains, NS point to the registrar, the registrar allows you to set A, CNAME, etc. records for domains and subdomains through the admin panel.
I expose A record to the myDomain.ru domain in the form of IP 30.10.10.20. Where the server with nginx is located. Everything is fine. But the server at 30.10.10.20 falls, but there is a backup, the same with the address 10.30.10.56, how to automatically switch to it, even if I go to change the A record at the registrar that has TTL, I will have to wait a long time. What are the solutions in such situations? Can eat pieces of iron which help to solve it? Maybe software?

Answer 1

What OS is on the servers?
If Linux, then there are utilities ucarp, vrrpd, keepalived, so that the backup server raises its IP address when the main one falls.
Setting example: habrahabr.ru/post/137476

Answer 2

The same task. But let me clarify a little:
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 3

https://www.digitalocean.com/community/tutorials/h...

Answer 4

You can set up a Pacemaker cluster with an ipaddr2 resource. The cluster will monitor the availability of the host and, if it falls, transfer the ip address to the backup node.