Creating a NixOS live CD

motivation

creating a modified NIXOS live CD out of a working nixos installation gives you the benefits:

verify what is included
no need to download it
it is easy to add your own programs to the image

how to build your own image

Create a file "iso.nix":

# This module defines a small NixOS installation CD.  It does not
# contain any graphical stuff.
{config, pkgs, ...}:
{
  imports = [
     <nixpkgs/nixos/modules/installer/cd-dvd/installation-cd-minimal.nix>
     <nixpkgs/nixos/modules/installer/cd-dvd/channel.nix>
  ];
}

Build the image via:

 nix-build -A config.system.build.isoImage -I nixos-config=iso.nix  /path/to/nixpkgs/nixos

Start SSH with your SSH key

In your iso.nix:

 services.openssh = {
   enable = true;
   hostKeys = [
     { bits = 8192; type = "ed25519"; path = "/etc/ssh/ssh_host_ed25519_key"; }
   ];
 };
 # enable ssh in the iso boot process
 systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
 users.users.root.openssh.authorizedKeys.keys [
   "ssh-rsa AAAAB3NzaC1y...== me@my-laptop"
 ];

software installation inside the 'once' deployed and booted image

in case you have booted from your image you can add software as described here:

install/remove software

references

See also section "Building your own NixOS CD" of the NixOS manual.