Gracefully exit if container runtime is misspelled

cmd/minikube/cmd/start.go

@@ -46,6 +46,7 @@ import (
 	"k8s.io/minikube/pkg/minikube/bootstrapper/images"
 	"k8s.io/minikube/pkg/minikube/config"
 	"k8s.io/minikube/pkg/minikube/constants"
+	"k8s.io/minikube/pkg/minikube/cruntime"
 	"k8s.io/minikube/pkg/minikube/download"
 	"k8s.io/minikube/pkg/minikube/driver"
 	"k8s.io/minikube/pkg/minikube/exit"
@@ -853,6 +854,21 @@ func validateFlags(cmd *cobra.Command, drvName string) {
 		}
 	}
 
+	if cmd.Flags().Changed(containerRuntime) {
+		runtime := strings.ToLower(viper.GetString(containerRuntime))
+
+		var validRuntime bool
+		for _, option := range cruntime.ValidRuntimes() {
+			if runtime == option {
+				validRuntime = true
+			}
+		}
+
+		if !validRuntime {
+			exit.UsageT(`Invalid Container Runtime: "{{.runtime}}". Valid runtimes are: {{.validOptions}}`, out.V{"runtime": runtime, "validOptions": strings.Join(cruntime.ValidRuntimes(), ", ")})
+		}
+	}
+
 	if driver.BareMetal(drvName) {
 		if ClusterFlagValue() != constants.DefaultClusterName {
 			exit.WithCodeT(exit.Config, "The '{{.name}} driver does not support multiple profiles: https://minikube.sigs.k8s.io/docs/reference/drivers/none/", out.V{"name": drvName})

cmd/minikube/cmd/start_flags.go

@@ -127,7 +127,7 @@ func initMinikubeFlags() {
 	startCmd.Flags().String(kicBaseImage, kic.BaseImage, "The base image to use for docker/podman drivers. Intended for local development.")
 	startCmd.Flags().Bool(keepContext, false, "This will keep the existing kubectl context and will create a minikube context.")
 	startCmd.Flags().Bool(embedCerts, false, "if true, will embed the certs in kubeconfig.")
-	startCmd.Flags().String(containerRuntime, "docker", "The container runtime to be used (docker, crio, containerd).")
+	startCmd.Flags().String(containerRuntime, "docker", fmt.Sprintf("The container runtime to be used (%s).", strings.Join(cruntime.ValidRuntimes(), ", ")))
 	startCmd.Flags().Bool(createMount, false, "This will start the mount daemon and automatically mount files into minikube.")
 	startCmd.Flags().String(mountString, constants.DefaultMountDir+":/minikube-host", "The argument to pass the minikube mount command on start.")
 	startCmd.Flags().StringArrayVar(&config.AddonList, "addons", nil, "Enable addons. see `minikube addons list` for a list of valid addon names.")

pkg/minikube/cruntime/cruntime.go

@@ -47,6 +47,11 @@ func (cs ContainerState) String() string {
 	return [...]string{"all", "running", "paused"}[cs]
 }
 
+// ValidRuntimes lists the supported container runtimes
+func ValidRuntimes() []string {
+	return []string{"docker", "crio", "containerd"}
+}
+
 // CommandRunner is the subset of command.Runner this package consumes
 type CommandRunner interface {
 	RunCmd(cmd *exec.Cmd) (*command.RunResult, error)