add support for adding and removing nodes to Minikube clusters started with --no-kubernetes

cmd/minikube/cmd/node_add.go

@@ -41,14 +41,25 @@ var nodeAddCmd = &cobra.Command{
 	Short: "Adds a node to the given cluster.",
 	Long:  "Adds a node to the given cluster config, and starts it.",
 	Run: func(cmd *cobra.Command, args []string) {
-		co := mustload.Healthy(ClusterFlagValue())
+		co := mustload.HealthyOrNoKubernetes(ClusterFlagValue())
 		cc := co.Config
 
 		if driver.BareMetal(cc.Driver) {
 			out.FailureT("none driver does not support multi-node clusters")
 		}
 
-		name := node.Name(len(cc.Nodes) + 1)
+		usedNodeNames := map[string]bool{}
+		for _, v := range cc.Nodes {
+			usedNodeNames[v.Name] = true
+		}
+
+		// find unused node name
+		ndx := 2
+		name := node.Name(ndx)
+		for usedNodeNames[name] {
+			ndx++
+			name = node.Name(ndx)
+		}
 
 		// for now control-plane feature is not supported
 		if cp {

cmd/minikube/cmd/node_delete.go

@@ -42,7 +42,7 @@ var nodeDeleteCmd = &cobra.Command{
 		}
 		name := args[0]
 
-		co := mustload.Healthy(ClusterFlagValue())
+		co := mustload.HealthyOrNoKubernetes(ClusterFlagValue())
 		out.Step(style.DeletingHost, "Deleting node {{.name}} from cluster {{.cluster}}", out.V{"name": name, "cluster": co.Config.Name})
 
 		n, err := node.Delete(*co.Config, name)

pkg/minikube/mustload/mustload.go

@@ -139,6 +139,23 @@ func Running(name string) ClusterController {
 	}
 }
 
+// HealthyOrNoKubernetes is a cmd-friendly way to load a healthy cluster
+// also allowing clusters without Kubernetes.
+func HealthyOrNoKubernetes(name string) ClusterController {
+	api, cc := Partial(name)
+
+	// if we're in a cluster that has Kubernetes deployed, expect it to be healthy.
+	if cc.KubernetesConfig.KubernetesVersion != constants.NoKubernetesVersion {
+		return Healthy(name)
+	}
+
+	// otherwise just add a node without Kubernetes.
+	return ClusterController{
+		API:    api,
+		Config: cc,
+	}
+}
+
 // Healthy is a cmd-friendly way to load a healthy cluster
 func Healthy(name string) ClusterController {
 	co := Running(name)

pkg/minikube/node/node.go

@@ -28,6 +28,7 @@ import (
 	"k8s.io/klog/v2"
 	"k8s.io/minikube/pkg/kapi"
 	"k8s.io/minikube/pkg/minikube/config"
+	"k8s.io/minikube/pkg/minikube/constants"
 	"k8s.io/minikube/pkg/minikube/machine"
 )
 
@@ -74,27 +75,22 @@ func Add(cc *config.ClusterConfig, n config.Node, delOnFail bool) error {
 }
 
 // drainNode drains then deletes (removes) node from cluster.
-func drainNode(cc config.ClusterConfig, name string) (*config.Node, error) {
-	n, _, err := Retrieve(cc, name)
-	if err != nil {
-		return n, errors.Wrap(err, "retrieve")
-	}
-
+func drainNode(n *config.Node, cc config.ClusterConfig) error {
 	m := config.MachineName(cc, *n)
 	api, err := machine.NewAPIClient()
 	if err != nil {
-		return n, err
+		return err
 	}
 
 	// grab control plane to use kubeconfig
 	host, err := machine.LoadHost(api, cc.Name)
 	if err != nil {
-		return n, err
+		return err
 	}
 
 	runner, err := machine.CommandRunner(host)
 	if err != nil {
-		return n, err
+		return err
 	}
 
 	// kubectl drain with extra options to prevent ending up stuck in the process
@@ -103,34 +99,41 @@ func drainNode(cc config.ClusterConfig, name string) (*config.Node, error) {
 	cmd := exec.Command("sudo", "KUBECONFIG=/var/lib/minikube/kubeconfig", kubectl, "drain", m,
 		"--force", "--grace-period=1", "--skip-wait-for-delete-timeout=1", "--disable-eviction", "--ignore-daemonsets", "--delete-emptydir-data", "--delete-local-data")
 	if _, err := runner.RunCmd(cmd); err != nil {
-		klog.Warningf("unable to drain node %q: %v", name, err)
+		klog.Warningf("unable to drain node %q: %v", n.Name, err)
 	} else {
-		klog.Infof("successfully drained node %q", name)
+		klog.Infof("successfully drained node %q", n.Name)
 	}
 
 	// kubectl delete
 	client, err := kapi.Client(cc.Name)
 	if err != nil {
-		return n, err
+		return err
 	}
 
 	// set 'GracePeriodSeconds: 0' option to delete node immediately (ie, w/o waiting)
 	var grace *int64
 	err = client.CoreV1().Nodes().Delete(context.Background(), m, v1.DeleteOptions{GracePeriodSeconds: grace})
 	if err != nil {
-		klog.Errorf("unable to delete node %q: %v", name, err)
-		return n, err
+		klog.Errorf("unable to delete node %q: %v", n.Name, err)
+		return err
 	}
-	klog.Infof("successfully deleted node %q", name)
+	klog.Infof("successfully deleted node %q", n.Name)
 
-	return n, nil
+	return nil
 }
 
 // Delete calls drainNode to remove node from cluster and deletes the host.
 func Delete(cc config.ClusterConfig, name string) (*config.Node, error) {
-	n, err := drainNode(cc, name)
+	n, _, err := Retrieve(cc, name)
 	if err != nil {
-		return n, err
+		return n, errors.Wrap(err, "retrieve")
+	}
+
+	if cc.KubernetesConfig.KubernetesVersion != constants.NoKubernetesVersion {
+		err := drainNode(n, cc)
+		if err != nil {
+			return n, err
+		}
 	}
 
 	m := config.MachineName(cc, *n)

pkg/minikube/node/start.go

@@ -311,8 +311,13 @@ func joinCluster(starter Starter, cpBs bootstrapper.Bootstrapper, bs bootstrappe
 	// avoid "error execution phase kubelet-start: a Node with name "<name>" and status "Ready" already exists in the cluster.
 	// You must delete the existing Node or change the name of this new joining Node"
 	if starter.PreExists {
+		n, _, err := Retrieve(*starter.Cfg, starter.Node.Name)
+		if err != nil {
+			return err
+		}
+
 		klog.Infof("removing existing worker node %q before attempting to rejoin cluster: %+v", starter.Node.Name, starter.Node)
-		if _, err := drainNode(*starter.Cfg, starter.Node.Name); err != nil {
+		if err := drainNode(n, *starter.Cfg); err != nil {
 			klog.Errorf("error removing existing worker node before rejoining cluster, will continue anyway: %v", err)
 		}
 		klog.Infof("successfully removed existing worker node %q from cluster: %+v", starter.Node.Name, starter.Node)