Where is the best place to configure netns in debian/ubuntu?

Question

linux

Colleagues, share your experience.
Where in Debian / Ubuntu is it more correct to write network namespaces and everything related to this? Creating namespaces, creating interface pairs, addresses, that's it.
And then a machine is brewing with a dozen namespaces with its own logic and all sorts of tunnels in each of them, and I really want not to get confused in this menagerie.