my understanding is that you can't sell this cloud as a service (AWS would not be able to use it)

It means all derivative works of microcloud must also be licensed AGPL (if someone else "links" other software into it, makes modifications and re-distributes, they must provide those modifications, etc).

Any company can sell microcloud, but it must remain AGPL.

This license choice is a defense against microcloud being assimilated into proprietary products.

(Now I'll guess at the motivation of your original question. Lemme know if I missed your point...) The AGPL doesn't apply to any containers or VMs running in a microcloud any more than Ubuntu's licensing applies to programs you run on Ubuntu.