CAPI changes for kubeadm cluster takeover

api/v1beta1/common_types.go

@@ -136,6 +136,9 @@ const (
 	// instead of being a source of truth for eventual consistency.
 	// This annotation can be used to inform MachinePool status during in-progress scaling scenarios.
 	ReplicasManagedByAnnotation = "cluster.x-k8s.io/replicas-managed-by"
+
+	// TakeOverCluster is the label used to mark the nodes that run on takeover-cluster instances.
+	TakeOverCluster = "cluster.x-k8s.io/takeover-cluster"
 )
 
 const (

bootstrap/kubeadm/internal/controllers/kubeadmconfig_controller.go

@@ -278,7 +278,7 @@ func (r *KubeadmConfigReconciler) Reconcile(ctx context.Context, req ctrl.Reques
 	}
 
 	// Note: can't use IsFalse here because we need to handle the absence of the condition as well as false.
-	if !conditions.IsTrue(cluster, clusterv1.ControlPlaneInitializedCondition) {
+	if !annotations.IsTakeOverCluster(cluster.GetObjectMeta()) && !conditions.IsTrue(cluster, clusterv1.ControlPlaneInitializedCondition) {
 		return r.handleClusterNotInitialized(ctx, scope)
 	}
 

controlplane/kubeadm/internal/controllers/controller.go

@@ -399,7 +399,7 @@ func (r *KubeadmControlPlaneReconciler) reconcile(ctx context.Context, cluster *
 		conditions.MarkFalse(controlPlane.KCP, controlplanev1.AvailableCondition, controlplanev1.WaitingForKubeadmInitReason, clusterv1.ConditionSeverityInfo, "")
 		return r.initializeControlPlane(ctx, cluster, kcp, controlPlane)
 	// We are scaling up
-	case numMachines < desiredReplicas && numMachines > 0:
+	case numMachines < desiredReplicas && numMachines >= 0:
 		// Create a new Machine w/ join
 		log.Info("Scaling up control plane", "Desired", desiredReplicas, "Existing", numMachines)
 		return r.scaleUpControlPlane(ctx, cluster, kcp, controlPlane)
@@ -568,7 +568,7 @@ func (r *KubeadmControlPlaneReconciler) reconcileEtcdMembers(ctx context.Context
 	log := ctrl.LoggerFrom(ctx)
 
 	// If etcd is not managed by KCP this is a no-op.
-	if !controlPlane.IsEtcdManaged() {
+	if annotations.IsTakeOverCluster(controlPlane.Cluster.GetObjectMeta()) || !controlPlane.IsEtcdManaged() {
 		return ctrl.Result{}, nil
 	}
 

controlplane/kubeadm/internal/controllers/helpers.go

@@ -74,8 +74,12 @@ func (r *KubeadmControlPlaneReconciler) reconcileKubeconfig(ctx context.Context,
 		return ctrl.Result{}, errors.Wrap(err, "failed to retrieve kubeconfig Secret")
 	}
 
-	if err := r.adoptKubeconfigSecret(ctx, cluster, configSecret, kcp); err != nil {
-		return ctrl.Result{}, err
+	// Check if the kubeconfig secret was created by v1alpha2 controllers, and thus it has the Cluster as the owner instead of KCP;
+	// If yes, adopt it.
+	if util.IsOwnedByObject(configSecret, cluster) && !util.IsControlledBy(configSecret, kcp) {
+		if err := r.adoptKubeconfigSecret(ctx, cluster, configSecret, kcp); err != nil {
+			return ctrl.Result{}, err
+		}
 	}
 
 	// only do rotation on owned secrets

internal/controllers/cluster/cluster_controller_phases.go

@@ -245,7 +245,10 @@ func (r *Reconciler) reconcileControlPlane(ctx context.Context, cluster *cluster
 		if err != nil {
 			return ctrl.Result{}, err
 		}
-		if initialized {
+
+		// TODO: PCP-22 set controlPlaneInitializedCondition to true for takeOver cluster
+		// as CP are already initialized in existing cluster
+		if annotations.IsTakeOverCluster(cluster.GetObjectMeta()) || initialized {
 			conditions.MarkTrue(cluster, clusterv1.ControlPlaneInitializedCondition)
 		} else {
 			conditions.MarkFalse(cluster, clusterv1.ControlPlaneInitializedCondition, clusterv1.WaitingForControlPlaneProviderInitializedReason, clusterv1.ConditionSeverityInfo, "Waiting for control plane provider to indicate the control plane has been initialized")

util/annotations/helpers.go

@@ -38,6 +38,11 @@ func IsExternallyManaged(o metav1.Object) bool {
 	return hasAnnotation(o, clusterv1.ManagedByAnnotation)
 }
 
+// IsTakeOverCluster returns true if the object has the `managed-by` annotation.
+func IsTakeOverCluster(o metav1.Object) bool {
+	return hasAnnotation(o, clusterv1.TakeOverCluster)
+}
+
 // HasPaused returns true if the object has the `paused` annotation.
 func HasPaused(o metav1.Object) bool {
 	return hasAnnotation(o, clusterv1.PausedAnnotation)