How to determine on the basis of FQDN on which database server to search for the data of the requested site?

Question

Algorithms

There is a task similar to domain parking, ie. the web server handles any domain that is asked of it. The infrastructure, in the future, should be scalable, in particular, sooner or later one database server will no longer cope with the load and additional ones will appear (denormalization). I want to immediately design the architecture, taking into account denormalization, so that later I don’t have to redo it through pain.
I just can't think of a reliable algorithm that will help the application understand which database server to search for data from a particular domain.
I will be glad to any advice! Thank you!

Answer 1

Either a config, or a meta-base, or hashing by some id.