I'm not sure. I think she's just looking to find out what's doable, what's not (Proof of Concept learning). She's not going to open the Pis to the Internet. I used to do this all the time when I had a server lab in my basement. I'd build and use something just to learn the concepts. Kubernetes is just an open-source system for automating deployment, scaling, and management of containerized applications. You can run containers applications and Kubernetes on your own infrastructure.