Hey, I am running a database and webserver, on one cloud instance (server1).

However I want to have a running backup (server2), so if I need to restart or update server1, i want server2 to be live on my domain. I could change the DNS but that takes 24 hours to react - there must be a better way? Some sort of load balancing server in front of server1 and server2, where I can switch where the traffic should go to? What can you recommend of servers/software for this?

Thanks