The preorders haven’t started yet, which I guess they just implemented by setting the stock to 0. Preorders open at the 1st of May at 9:00AM PST according to the product page.

You can use environment.etc to manage a file in /etc: https://search.nixos.org/options?show=environment.etc.

Kubernetes and docker both use containerd, which in turn uses runc which is what the vulnerability is in.