func RequiredNodeImages(cfg *config.Cluster) sets.String {
	images := sets.NewString()
	for _, node := range cfg.Nodes {
		images.Insert(node.Image)
	}
	return images
}
RequiredNodeImages returns the set of _node_ images specified by the config
This does not include the loadbalancer image, and is only used to improve
the UX by explicit pulling the node images prior to running
package common
import (
	"k8s.io/apimachinery/pkg/util/sets"
	"sigs.k8s.io/kind/pkg/internal/apis/config"
)