Add warning if disk image is missing features

pkg/minikube/cruntime/docker.go

@@ -33,6 +33,19 @@ import (
 // KubernetesContainerPrefix is the prefix of each kubernetes container
 const KubernetesContainerPrefix = "k8s_"
 
+type ErrISOFeature struct {
+	missing string
+}
+
+func NewErrISOFeature(missing string) *ErrISOFeature {
+	return &ErrISOFeature{
+		missing: missing,
+	}
+}
+func (e *ErrISOFeature) Error() string {
+	return e.missing
+}
+
 // Docker contains Docker runtime state
 type Docker struct {
 	Socket string
@@ -278,7 +291,7 @@ func (r *Docker) Preload(k8sVersion string) error {
 
 	c := exec.Command("which", "lz4")
 	if _, err := r.Runner.RunCmd(c); err != nil {
-		return errors.Wrapf(err, "check lz4 available.")
+		return NewErrISOFeature("lz4")
 	}
 
 	// Copy over tarball into host

pkg/minikube/node/config.go

@@ -68,7 +68,13 @@ func configureRuntimes(runner cruntime.CommandRunner, drvName string, k8s config
 	}
 	if !driver.IsKIC(drvName) {
 		if err := cr.Preload(k8s.KubernetesVersion); err != nil {
-			glog.Errorf("Failed to preload container runtime %s: %v, falling back to caching images", cr.Name(), err)
+			switch err.(type) {
+			case *cruntime.ErrISOFeature:
+				out.T(out.Tip, "Existing disk is missing new features ({{.error}}). To upgrade, run 'minikube delete'", out.V{"error": err})
+			default:
+				glog.Warningf("%s preload failed: %v, falling back to caching images", cr.Name(), err)
+			}
+
 			if err := machine.CacheImagesForBootstrapper(k8s.ImageRepository, k8s.KubernetesVersion, viper.GetString(cmdcfg.Bootstrapper)); err != nil {
 				exit.WithError("Failed to cache images", err)
 			}