How to use OpenVPN exclusively for a single application?

Question

openvpn

It is necessary to pass the connection of three copies of one program through openvpn, provided that the rest of the software accesses the Internet directly.

Answer 1

man 7 namespaces

Answer 2

In your situation, we do the following:
We remove the positions in the openvpn config (for clients) that are responsible for assigning the main route.
And we create static routes to your server and tell them to walk through the VPN, if everything works, we will find out on the openvpn.net website how to register routes in the config.
Is the idea clear?