docs: function service(root, cb) {
      var registryPath = config.registryPath || path.join(root, 'registry');
      fs.mkdir(registryPath, function(err) {
        if (err && err.code !== 'EEXIST') {
          logger.error(err);
          return cb(err);
        }
  
        // swallow errors, it may exists
        var server = registry({
          dir: registryPath
        });
  
        server.on('error', function(err) {
          logger.error(err);
        });
  
        server.listen(config.registryPort, function(err) {
          logger.info({
            port: config.registryPort,
            path: registryPath
          }, 'registry started');
  
          if (typeof err === 'string') {
            // err will contains the ip
            // TODO remove me as https://github.com/mafintosh/root/issues/12 get fixes
            err = null;
          }
  
          if (cb) {
            cb(err, server);
          }
        });
      });
    }