Restart containerd after stopping alternate runtimes

After stopping any runtimes that aren't being used, if we're using
containerd then we need to restart it. This is because it competes with
cri-o to listen on port 10010, causing a necesary plugin to not be
installed. After stopping cri-o, we need to restart containerd so that
the plugin is installed.

I also added some preflight checks when using alternative runtimes.
kubeadm checks to make sure the Docker service is running, so I disabled
that. It also checks if a few ports are available; these are ports that
containerd uses, so I also added them to the ignore list.

This should finish the work started in kubernetes#3211, which stopped alternative
runtimes but didn't restart containerd. I was able to run "minikube
start" with containerd locally with this change.

cmd/minikube/cmd/start.go

@@ -295,31 +295,39 @@ func runStart(cmd *cobra.Command, args []string) {
 	fmt.Println("Stopping extra container runtimes...")
 
 	containerRuntime := viper.GetString(containerRuntime)
-	if config.VMDriver != "none" && containerRuntime != "" {
+	if config.VMDriver != constants.DriverNone && containerRuntime != "" {
 		if _, err := host.RunSSHCommand("sudo systemctl stop docker"); err == nil {
 			_, err = host.RunSSHCommand("sudo systemctl stop docker.socket")
 		}
 		if err != nil {
-			glog.Errorf("Error stopping docker", err)
+			glog.Errorf("Error stopping docker: %v", err)
 		}
 	}
-	if config.VMDriver != "none" && (containerRuntime != "crio" && containerRuntime != "cri-o") {
+	if config.VMDriver != constants.DriverNone && (containerRuntime != constants.CrioRuntime && containerRuntime != constants.Cri_oRuntime) {
 		if _, err := host.RunSSHCommand("sudo systemctl stop crio"); err != nil {
-			glog.Errorf("Error stopping crio", err)
+			glog.Errorf("Error stopping crio: %v", err)
 		}
 	}
-	if config.VMDriver != "none" && containerRuntime != "rkt" {
+	if config.VMDriver != constants.DriverNone && containerRuntime != constants.RktRuntime {
 		if _, err := host.RunSSHCommand("sudo systemctl stop rkt-api"); err == nil {
 			_, err = host.RunSSHCommand("sudo systemctl stop rkt-metadata")
 		}
 		if err != nil {
-			glog.Errorf("Error stopping rkt", err)
+			glog.Errorf("Error stopping rkt: %v", err)
+		}
+	}
+
+	if config.VMDriver != constants.DriverNone && containerRuntime == constants.ContainerdRuntime {
+		fmt.Println("Restarting containerd runtime...")
+		// restart containerd so that it can install all plugins
+		if _, err := host.RunSSHCommand("sudo systemctl restart containerd"); err != nil {
+			glog.Errorf("Error restarting containerd: %v", err)
 		}
 	}
 
 	fmt.Println("Starting cluster components...")
 
-	if !exists || config.VMDriver == "none" {
+	if !exists || config.VMDriver == constants.DriverNone {
 		if err := k8sBootstrapper.StartCluster(kubernetesConfig); err != nil {
 			glog.Errorln("Error starting cluster: ", err)
 			cmdutil.MaybeReportErrorAndExit(err)

pkg/minikube/bootstrapper/kubeadm/kubeadm.go

@@ -115,6 +115,10 @@ func (k *KubeadmBootstrapper) StartCluster(k8s config.KubernetesConfig) error {
 	}
 
 	b := bytes.Buffer{}
+	preflights := constants.Preflights
+	if k8s.ContainerRuntime != "" {
+		preflights = constants.AlternateRuntimePreflights
+	}
 	templateContext := struct {
 		KubeadmConfigFile   string
 		SkipPreflightChecks bool
@@ -125,7 +129,7 @@ func (k *KubeadmBootstrapper) StartCluster(k8s config.KubernetesConfig) error {
 		SkipPreflightChecks: !VersionIsBetween(version,
 			semver.MustParse("1.9.0-alpha.0"),
 			semver.Version{}),
-		Preflights: constants.Preflights,
+		Preflights: preflights,
 		DNSAddon:   "kube-dns",
 	}
 	if version.GTE(semver.MustParse("1.12.0")) {

pkg/minikube/constants/constants.go

@@ -164,6 +164,23 @@ var Preflights = []string{
 	"CRI",
 }
 
+// AlternateRuntimePreflights are additional preflight checks applied when running
+// any container runtime that isn't Docker
+var AlternateRuntimePreflights = append(Preflights, []string{
+	"Service-Docker",
+	"Port-8443",
+	"Port-10251",
+	"Port-10252",
+	"Port-2379",
+}...)
+
+const (
+	ContainerdRuntime = "containerd"
+	RktRuntime        = "rkt"
+	CrioRuntime       = "crio"
+	Cri_oRuntime      = "cri-o"
+)
+
 const (
 	DefaultUfsPort       = "5640"
 	DefaultUfsDebugLvl   = 0