Quickly create a NixOS snapshot on Hetzner Cloud using Packer.

create-hcloud-nixos-snapshot \
  --location hel1 \
  --server-type cax11 \
  --ssh-key "$SSH_KEY"

#  --host-name nixos
#  --save-config-to $PWD
#  --help

If the script succeeds, it'll save generated hardware-configuration.nix file in current working directory or directory configured via --save-config-to. Once created, the snapshot can be referenced by tools such as Terraform during provisioning pipeline.

The script is exported at packages.${system}.default and can be installed via Nix flakes. For example,

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    chns = {
      url = "github:kyswtn/create-hcloud-nixos-snapshot";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs = { self, nixpkgs, chns, ... }:
    let
      system = "aarch64-darwin";
      nixpkgs = nixpkgs.legacyPackages.${system};
      create-hcloud-nixos-snapshot = chns.packages.${system}.default;
    in
    {
      devShells.${system}.default = pkgs.mkShellNoCC {
        packages = [
          create-hcloud-nixos-snapshot
        ];
      };
    };
}

Generated snapshot is intentionally as minimal as possible, and only installs SSH with Public Key Authentication and Tailscale. Once a machine has been provisioned based off the snapshot, use nixos-rebuild with --target-host to rebuild with desired new configuration.

This script installs NixOS exactly how the official documentation guides you to. If nixos-anywhere or nixos-infect is too overwhelming, this is for you. Until Hetzner officially provides NixOS standard images, this script will be handy. Especially for those who don't want to maintain extra configurations.