How do systems like ucoz work?

Question

PHP

Hello! I am very interested in the question of how systems like ucoz function when the same engine is on different subdomains, in particular, it is interesting how the database is arranged (is a separate database or table created for each new domain), and how do they do it so that on the same engine, different users (subdomains) had their own settings / design / modules (I'm interested in the technical side of the issue in a nutshell), etc.

Answer 1

The script receives the domain name as one of the input arguments.
In the database, all data is indicated to which domain they belong.
Well, sharding is additionally applied:
All data is divided into separate nodes by domains, by NNN domains in a node.
Each node is a separate database.
Nodes are already mapped to physical servers.
Accordingly, when the script is launched on the backend, it receives the name of the domain, determines the node and the physical server from it, and connects there.
This is a general scheme for the operation of all loaded services.
Specifically, in the case of ucoz, it may be more profitable for them to additionally save everything to static.