anchor.diff:      caFile = mkOption {
         description = "${prefix} certificate authrority file used to connect to kube-apiserver.";
         type = types.nullOr types.path;
  -      default = null;
  +      default = cfg.caFile;
       };
   
       certFile = mkOption {
  
positive.code: 
        caFile = mkOption {
          description = "Etcd ca file.";
          default = null;
          type = types.nullOr types.path;
        };
      };
  
      kubeconfig = mkKubeConfigOptions "Default kubeconfig";
  
      dataDir = mkOption {
        description = "Kubernetes root directory for managing kubelet files.";
  
negative.code: 
        clientCaFile = mkOption {
          description = "Kubernetes apiserver CA file for client auth.";
          default = cfg.caFile;
          type = types.nullOr types.path;
        };
  
  