anchor.diff:  
           path =
             [ pkgs.sudo pkgs.vlan pkgs.nettools pkgs.iptables pkgs.qemu_kvm
  -            pkgs.e2fsprogs pkgs.utillinux pkgs.multipath_tools
  +            pkgs.e2fsprogs pkgs.utillinux pkgs.multipath_tools pkgs.iproute
  +            pkgs.bridge_utils
             ];
   
           exec = "${nova}/bin/nova-compute --flagfile=${novaConf}";
  
positive.code: 
    config = mkIf cfg.enableSingleNode {
  
      environment.systemPackages = [ nova pkgs.euca2ools ];
  
      environment.etc =
        [ # The Paste configuration file for nova-api.
  
negative.code:         # Allow the CA certificate generation script (called by
          # nova-api) to work.
          mkdir -m 700 -p /var/lib/nova/CA /var/lib/nova/CA/private
  
          # Initialise the SQLite database.        
          ${nova}/bin/nova-manage db sync
  