code: func newJoinOptions() *joinOptions {
  	// initialize the public kubeadm config API by applying defaults
  	externalcfg := &kubeadmapiv1beta2.JoinConfiguration{}
  
  	// Add optional config objects to host flags.
  	// un-set objects will be cleaned up afterwards (into newJoinData func)
  	externalcfg.Discovery.File = &kubeadmapiv1beta2.FileDiscovery{}
  	externalcfg.Discovery.BootstrapToken = &kubeadmapiv1beta2.BootstrapTokenDiscovery{}
  	externalcfg.ControlPlane = &kubeadmapiv1beta2.JoinControlPlane{}
  
  	// Apply defaults
  	kubeadmscheme.Scheme.Default(externalcfg)
  
  	return &joinOptions{
  		externalcfg: externalcfg,
  	}
  }
docs: // newJoinOptions returns a struct ready for being used for creating cmd join flags.