Support Hetzner and ISO attach API

[alexanderkjeldaas]

It would be nice to support an optional argument to the script, an API key.

With the API key, it should be possible to attach an ISO with NixOS to the server and at least use the store on that ISO as cache, or install whatever version is on that ISO.

For Hetzner Cloud, this API https://docs.hetzner.cloud/#resources-server-actions-post-13 is relevant.

Attaching an ISO like that would make it possible to read and write directly over SSD and local network, potentially making the installation very fast.

[elitak]

Do you mean having nixos-infect use the ISO as a binary cache? If so, that'd be doable just by running whatever command or two mounts the ISO as a preamble to calling nixos-infect. nixos-infect itself would need a way to pass that binary cache path on to the invocation of nix-env it uses. Trying to get the bootstrapping working off of the ISO may be a lot more involved, so I would advise against it, especially for the sake of saving < 100MB of downloading.

Try tweaking the script to get it to work for you. If you get either working with minimal modification, I will put in changes to allow binary caches to be passed into the appropriate invocations.