Add MachineDeployment rolloutAfter support

api/v1alpha4/machinedeployment_types.go

@@ -33,7 +33,8 @@ const (
 	OnDeleteMachineDeploymentStrategyType MachineDeploymentStrategyType = "OnDelete"
 
 	// RevisionAnnotation is the revision annotation of a machine deployment's machine sets which records its rollout sequence.
-	RevisionAnnotation = "machinedeployment.clusters.x-k8s.io/revision"
+	RevisionAnnotation     = "machinedeployment.clusters.x-k8s.io/revision"
+	RolloutAfterAnnotation = "machinedeployment.clusters.x-k8s.io/RolloutAfterAnnotation"
 
 	// RevisionHistoryAnnotation maintains the history of all old revisions that a machine set has served for a machine deployment.
 	RevisionHistoryAnnotation = "machinedeployment.clusters.x-k8s.io/revision-history"
@@ -57,6 +58,11 @@ type MachineDeploymentSpec struct {
 	// +kubebuilder:validation:MinLength=1
 	ClusterName string `json:"clusterName"`
 
+	// RolloutAfter performs a rollout of the entire cluster one component at a time,
+	// control plane first and then machine deployments.
+	// +optional
+	RolloutAfter *metav1.Time `json:"rolloutAfter,omitempty"`
+
 	// Number of desired machines. Defaults to 1.
 	// This is a pointer to distinguish between explicit zero and not specified.
 	// +optional

controllers/machinedeployment_controller.go

@@ -220,6 +220,15 @@ func (r *MachineDeploymentReconciler) reconcile(ctx context.Context, cluster *cl
 		return ctrl.Result{}, errors.Errorf("missing MachineDeployment strategy")
 	}
 
+	// TODO (alberto): store this in the reconciler.
+	now := metav1.Now()
+	if now.After(d.Spec.RolloutAfter.Time) &&
+		d.Spec.RolloutAfter.Time.String() != d.Spec.Template.Labels[clusterv1.RolloutAfterAnnotation] {
+		// Triggers rolling update.
+		d.Spec.Template.Labels[clusterv1.RolloutAfterAnnotation] = d.Spec.RolloutAfter.String()
+		return ctrl.Result{}, r.Client.Update(ctx, d)
+	}
+
 	if d.Spec.Strategy.Type == clusterv1.RollingUpdateMachineDeploymentStrategyType {
 		if d.Spec.Strategy.RollingUpdate == nil {
 			return ctrl.Result{}, errors.Errorf("missing MachineDeployment settings for strategy type: %s", d.Spec.Strategy.Type)