Enable k3s cluster upgrades

internal/controller/reconcile_kubernetes.go

@@ -3,9 +3,11 @@ package controller
 import (
 	"context"
 	"fmt"
+	"strings"
 
 	lifecyclev1alpha1 "github.com/suse-edge/upgrade-controller/api/v1alpha1"
 	"github.com/suse-edge/upgrade-controller/internal/upgrade"
+	"github.com/suse-edge/upgrade-controller/pkg/release"
 	corev1 "k8s.io/api/core/v1"
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -14,21 +16,26 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
-func (r *UpgradePlanReconciler) reconcileKubernetes(ctx context.Context, upgradePlan *lifecyclev1alpha1.UpgradePlan, kubernetesVersion string) (ctrl.Result, error) {
+func (r *UpgradePlanReconciler) reconcileKubernetes(ctx context.Context, upgradePlan *lifecyclev1alpha1.UpgradePlan, release *release.Release) (ctrl.Result, error) {
+	nodeList := &corev1.NodeList{}
+	if err := r.List(ctx, nodeList); err != nil {
+		return ctrl.Result{}, fmt.Errorf("listing nodes: %w", err)
+	}
+
+	kubernetesVersion, err := targetKubernetesVersion(nodeList, release)
+	if err != nil {
+		return ctrl.Result{}, fmt.Errorf("identifying target kubernetes version: %w", err)
+	}
+
 	controlPlanePlan := upgrade.KubernetesControlPlanePlan(kubernetesVersion)
-	if err := r.Get(ctx, client.ObjectKeyFromObject(controlPlanePlan), controlPlanePlan); err != nil {
+	if err = r.Get(ctx, client.ObjectKeyFromObject(controlPlanePlan), controlPlanePlan); err != nil {
 		if !errors.IsNotFound(err) {
 			return ctrl.Result{}, err
 		}
 
 		return ctrl.Result{}, r.createPlan(ctx, upgradePlan, controlPlanePlan)
 	}
 
-	nodeList := &corev1.NodeList{}
-	if err := r.List(ctx, nodeList); err != nil {
-		return ctrl.Result{}, fmt.Errorf("listing nodes: %w", err)
-	}
-
 	selector, err := metav1.LabelSelectorAsSelector(controlPlanePlan.Spec.NodeSelector)
 	if err != nil {
 		return ctrl.Result{}, fmt.Errorf("parsing node selector: %w", err)
@@ -65,6 +72,23 @@ func (r *UpgradePlanReconciler) reconcileKubernetes(ctx context.Context, upgrade
 	return ctrl.Result{Requeue: true}, nil
 }
 
+func targetKubernetesVersion(nodeList *corev1.NodeList, release *release.Release) (string, error) {
+	if len(nodeList.Items) == 0 {
+		return "", fmt.Errorf("unable to determine current kubernetes version due to empty node list")
+	}
+
+	kubeletVersion := nodeList.Items[0].Status.NodeInfo.KubeletVersion
+
+	switch {
+	case strings.Contains(kubeletVersion, "k3s"):
+		return release.Components.Kubernetes.K3S.Version, nil
+	case strings.Contains(kubeletVersion, "rke2"):
+		return release.Components.Kubernetes.RKE2.Version, nil
+	default:
+		return "", fmt.Errorf("upgrading from kubernetes version %s is not supported", kubeletVersion)
+	}
+}
+
 func isKubernetesUpgraded(nodeList *corev1.NodeList, selector labels.Selector, kubernetesVersion string) bool {
 	for _, node := range nodeList.Items {
 		if !selector.Matches(labels.Set(node.Labels)) {

internal/controller/upgradeplan_controller.go

@@ -88,7 +88,7 @@ func (r *UpgradePlanReconciler) executePlan(ctx context.Context, upgradePlan *li
 	// Upgrade OS here...
 
 	if !meta.IsStatusConditionTrue(upgradePlan.Status.Conditions, lifecyclev1alpha1.KubernetesUpgradedCondition) {
-		return r.reconcileKubernetes(ctx, upgradePlan, release.Components.Kubernetes.RKE2.Version)
+		return r.reconcileKubernetes(ctx, upgradePlan, release)
 	}
 
 	// Upgrade rest of the components here...

internal/upgrade/kubernetes.go

@@ -11,6 +11,7 @@ import (
 
 const (
 	rke2UpgradeImage = "rancher/rke2-upgrade"
+	k3sUpgradeImage  = "rancher/k3s-upgrade"
 
 	controlPlaneKey = "control-plane"
 	workersKey      = "workers"
@@ -20,12 +21,21 @@ func kubernetesPlanName(typeKey, version string) string {
 	return fmt.Sprintf("%s-%s", typeKey, strings.ReplaceAll(version, "+", "-"))
 }
 
+func kubernetesUpgradeImage(version string) string {
+	if strings.Contains(version, "k3s") {
+		return k3sUpgradeImage
+	}
+
+	return rke2UpgradeImage
+}
+
 func KubernetesControlPlanePlan(version string) *upgradecattlev1.Plan {
 	controlPlanePlanName := kubernetesPlanName(controlPlaneKey, version)
+	upgradeImage := kubernetesUpgradeImage(version)
 
 	controlPlanePlan := baseUpgradePlan(controlPlanePlanName)
 	controlPlanePlan.Labels = map[string]string{
-		"rke2-upgrade": "control-plane",
+		"k8s-upgrade": "control-plane",
 	}
 	controlPlanePlan.Spec.NodeSelector = &metav1.LabelSelector{
 		MatchExpressions: []metav1.LabelSelectorRequirement{
@@ -40,7 +50,7 @@ func KubernetesControlPlanePlan(version string) *upgradecattlev1.Plan {
 	}
 	controlPlanePlan.Spec.Concurrency = 1
 	controlPlanePlan.Spec.Upgrade = &upgradecattlev1.ContainerSpec{
-		Image: rke2UpgradeImage,
+		Image: upgradeImage,
 	}
 	controlPlanePlan.Spec.Version = version
 	controlPlanePlan.Spec.Cordon = true
@@ -71,10 +81,11 @@ func KubernetesControlPlanePlan(version string) *upgradecattlev1.Plan {
 func KubernetesWorkerPlan(version string) *upgradecattlev1.Plan {
 	controlPlanePlanName := kubernetesPlanName(controlPlaneKey, version)
 	workerPlanName := kubernetesPlanName(workersKey, version)
+	upgradeImage := kubernetesUpgradeImage(version)
 
 	workerPlan := baseUpgradePlan(workerPlanName)
 	workerPlan.Labels = map[string]string{
-		"rke2-upgrade": "worker",
+		"k8s-upgrade": "worker",
 	}
 	workerPlan.Spec.Concurrency = 2
 	workerPlan.Spec.NodeSelector = &metav1.LabelSelector{
@@ -93,10 +104,10 @@ func KubernetesWorkerPlan(version string) *upgradecattlev1.Plan {
 			"prepare",
 			controlPlanePlanName,
 		},
-		Image: rke2UpgradeImage,
+		Image: upgradeImage,
 	}
 	workerPlan.Spec.Upgrade = &upgradecattlev1.ContainerSpec{
-		Image: rke2UpgradeImage,
+		Image: upgradeImage,
 	}
 	workerPlan.Spec.Version = version
 	workerPlan.Spec.Cordon = true