anchor.diff:  
       (mkIf (any (el: el == "node") cfg.roles) {
         virtualisation.docker.enable = mkDefault true;
  -      services.cadvisor.enable = mkDefault true;
  -      services.cadvisor.port = mkDefault 4194;
         services.kubernetes.kubelet.enable = mkDefault true;
         services.kubernetes.proxy.enable = mkDefault true;
       })
  
positive.code:           export PATH="/bin:/sbin:/usr/bin:/usr/sbin:$PATH"
            exec ${cfg.package}/bin/kubelet \
              --api-servers=${concatMapStringsSep "," (f: "http://${f}") cfg.kubelet.apiServers}  \
              --address=${cfg.kubelet.address} \
              --port=${toString cfg.kubelet.port} \
              --hostname-override=${cfg.kubelet.hostname} \
  
negative.code: 
        machines = mkOption {
          description = "Kubernetes controller list of machines to schedule to schedule onto";
          default = [];
          type = types.listOf types.str;
        };
  
  