Merge pull request #11928 from chrischdi/pr-machineset-precheck-topology-upgrade-pending

✨ machineset: Extend ControlPlaneIsStable preflight check to check for a pending topology based ControlPlane version upgrade

Author: k8s-ci-robot

docs/book/src/tasks/experimental-features/machineset-preflight-checks.md

@@ -18,7 +18,7 @@ Enabling `MachineSetPreflightChecks` provides safety in such circumstances by ma
 
 ### `ControlPlaneIsStable`
 
-* This preflight check ensures that the ControlPlane is currently stable i.e. the ControlPlane is currently neither provisioning nor upgrading.   
+* This preflight check ensures that the ControlPlane is currently stable i.e. the ControlPlane is currently neither provisioning, upgrading nor pending an upgrade.   
 * This preflight check is only performed if:
   * The Cluster uses a ControlPlane provider.
   * ControlPlane version is defined (`ControlPlane.spec.version` is set).

internal/controllers/machineset/machineset_preflight.go

@@ -91,7 +91,7 @@ func (r *Reconciler) runPreflightChecks(ctx context.Context, cluster *clusterv1.
 	preflightCheckErrs := []preflightCheckErrorMessage{}
 	// Run the control-plane-stable preflight check.
 	if !skipped.Has(clusterv1.MachineSetPreflightCheckControlPlaneIsStable) {
-		preflightCheckErr, err := r.controlPlaneStablePreflightCheck(controlPlane)
+		preflightCheckErr, err := r.controlPlaneStablePreflightCheck(controlPlane, cluster, *cpVersion)
 		if err != nil {
 			errList = append(errList, err)
 		}
@@ -142,9 +142,15 @@ func (r *Reconciler) runPreflightChecks(ctx context.Context, cluster *clusterv1.
 	return nil, nil
 }
 
-func (r *Reconciler) controlPlaneStablePreflightCheck(controlPlane *unstructured.Unstructured) (preflightCheckErrorMessage, error) {
+func (r *Reconciler) controlPlaneStablePreflightCheck(controlPlane *unstructured.Unstructured, cluster *clusterv1.Cluster, controlPlaneVersion string) (preflightCheckErrorMessage, error) {
 	cpKlogRef := klog.KRef(controlPlane.GetNamespace(), controlPlane.GetName())
 
+	if feature.Gates.Enabled(feature.ClusterTopology) {
+		if cluster.Spec.Topology != nil && cluster.Spec.Topology.Version != controlPlaneVersion {
+			return ptr.To(fmt.Sprintf("%s %s has a pending version upgrade to %s (%q preflight check failed)", controlPlane.GetKind(), cpKlogRef, cluster.Spec.Topology.Version, clusterv1.MachineSetPreflightCheckControlPlaneIsStable)), nil
+		}
+	}
+
 	// Check that the control plane is not provisioning.
 	isProvisioning, err := contract.ControlPlane().IsProvisioning(controlPlane)
 	if err != nil {

internal/controllers/machineset/machineset_preflight_test.go

@@ -36,6 +36,7 @@ import (
 )
 
 func TestMachineSetReconciler_runPreflightChecks(t *testing.T) {
+	utilfeature.SetFeatureGateDuringTest(t, feature.Gates, feature.ClusterTopology, true)
 	ns := "ns1"
 
 	controlPlaneWithNoVersion := builder.ControlPlane(ns, "cp1").Build()
@@ -169,6 +170,26 @@ func TestMachineSetReconciler_runPreflightChecks(t *testing.T) {
 				},
 				wantErr: false,
 			},
+			{
+				name: "control plane preflight check: should fail if the cluster defines a different version than the control plane",
+				cluster: &clusterv1.Cluster{
+					ObjectMeta: metav1.ObjectMeta{
+						Namespace: ns,
+					},
+					Spec: clusterv1.ClusterSpec{
+						ControlPlaneRef: contract.ObjToRef(controlPlaneStable),
+						Topology: &clusterv1.Topology{
+							Version: "v1.27.2",
+						},
+					},
+				},
+				controlPlane: controlPlaneStable,
+				machineSet:   &clusterv1.MachineSet{},
+				wantMessages: []string{
+					"GenericControlPlane ns1/cp1 has a pending version upgrade to v1.27.2 (\"ControlPlaneIsStable\" preflight check failed)",
+				},
+				wantErr: false,
+			},
 			{
 				name: "control plane preflight check: should pass if the control plane is upgrading but the preflight check is skipped",
 				cluster: &clusterv1.Cluster{