I don't understand how to setup a failover for my quite simple scenario. I am building a service gateway for API. What I want to have is two servers
hosted in different datacenters. And I simply want the user to be able to access the service even if one of the servers is down. There is no issue with DB sync, I only care about availability of the service.
How do I do that while preventing the user to implement any kind of failover logic on their end? I want the user to be given a single domain or a single IP address and be able to access the service all the time using this single end point.
What I do not understand is how this can be achieved. I know I can setup a network node that will forward the requests to the first or second server, depending on which of those two is currently online. However, I fail to see how this setup solved HA problem as we just introduced a single point of failure to the system - the forwarding node. So, if this node goes down, the service is unavailable.
Could you please explain how to implement this in the real world? Is it possible to achieve this with reasonable cost
(i.e. not more than a cost of hosting of the servers themselves).
Edit: It has been suggested that different datacenters requirement is costly. So, feel free to provide suggestions for 2 servers within 1 datacenter.
Edit 2: Feel free to mention what is a reasonable cost for the that setup.