1. Setup libvirtd according to https://nixos.org/nixops/manual/#idm140737319108016

2. Create `dummy.nix`:

$ cat dummy.nix
{
  dummy = {
    deployment.targetEnv = "libvirtd";
    deployment.libvirtd.headless = true;
}

3. nixops create -d dummy ./dummy.nix

4. nixops deploy -d dummy -I ~/wherenixpkgsmasterfolderlies