I was going to set up a VirtualBox virtual network disconnected from the Internet to do this - perhaps only allowing HTTPS to a Debian/Ubuntu mirror if I need t

I was going to set up a VirtualBox virtual network disconnected from the Internet to do this - perhaps only allowing HTTPS to a Debian/Ubuntu mirror if I need to install packages. You could do something similar for your Kubernetes cluster. I was also considering a cheap, pay-by-the hour VPS that I could just destroy after the stream.