{
  network.rollBack = false;
  friot = {pkgs, lib, config, options, ...}:
    let ipv4 = if options.networking.privateIPv4.isDefined
               then config.networking.privateIPv4
               else "X.X.X.X";
    in {
    config = {
      deployment.targetEnv             = "virtualbox";
      deployment.virtualbox.headless   = true;
      deployment.virtualbox.memorySize = 1024;
      deployment.virtualbox.vcpu       = 2;
      deployment.virtualbox.disks.disk1.baseImage = ../../.var/nixops/virtualbox.vmdk;
      #deployment.virtualbox.disks.disk1.size = 6024;
       # NOTE: resize not yet supported.

      deployment.storeKeysOnMachine = true;
      networking = {
        interfaces."enp0s8" = {
          #macAddress = "00:11:22:33:44:55";
          #ipv4.addresses = [ { address = ipv4; prefixLength = 32; } ];
          ipv6.addresses = [ { address = "fe80::1"; prefixLength = 10; } ];
        };
        zones = {
          net = {
            iface = "enp0s3";
            ipv4  = ipv4;
          };
          lan = {
            iface = "enp0s8";
            ipv4  = ipv4;
            #ipv6  = "fe80::1";
          };
        };
      };
    };
  };
}

#{
#  vbox =
#    { deployment.targetEnv = "virtualbox"; };
#
#  machine =
#    { resources, ... }:
#    { deployment.targetEnv = "container";
#      deployment.container.host = resources.machines.vbox;
#    };
#}