✨ Add rolloutAfter to cluster.spec.topology (#13391)

* Add rolloutAfter to cluster.spec.topology

* Address comments

Author: fabriziopandini

api/core/v1beta1/conversion.go

@@ -75,10 +75,12 @@ func (src *Cluster) ConvertTo(dstRaw conversion.Hub) error {
 
 	if ok {
 		dst.Spec.Topology.ControlPlane.HealthCheck.Checks.UnhealthyMachineConditions = restored.Spec.Topology.ControlPlane.HealthCheck.Checks.UnhealthyMachineConditions
+		dst.Spec.Topology.ControlPlane.Rollout = restored.Spec.Topology.ControlPlane.Rollout
 		for _, restoredMD := range restored.Spec.Topology.Workers.MachineDeployments {
 			for i, dstMD := range dst.Spec.Topology.Workers.MachineDeployments {
 				if restoredMD.Name == dstMD.Name {
 					dst.Spec.Topology.Workers.MachineDeployments[i].HealthCheck.Checks.UnhealthyMachineConditions = restoredMD.HealthCheck.Checks.UnhealthyMachineConditions
+					dst.Spec.Topology.Workers.MachineDeployments[i].Rollout.After = restoredMD.Rollout.After
 				}
 			}
 		}

api/core/v1beta1/zz_generated.conversion.go

@@ -632,6 +632,10 @@ type ControlPlaneTopology struct {
 	// +optional
 	Replicas *int32 `json:"replicas,omitempty"`
 
+	// rollout allows you to configure the behavior of rolling updates to the control plane.
+	// +optional
+	Rollout ControlPlaneTopologyRolloutSpec `json:"rollout,omitempty,omitzero"`
+
 	// healthCheck allows to enable, disable and override control plane health check
 	// configuration from the ClusterClass for this control plane.
 	// +optional
@@ -662,6 +666,18 @@ type ControlPlaneTopology struct {
 	Variables ControlPlaneVariables `json:"variables,omitempty,omitzero"`
 }
 
+// ControlPlaneTopologyRolloutSpec defines the rollout behavior.
+// +kubebuilder:validation:MinProperties=1
+type ControlPlaneTopologyRolloutSpec struct {
+	// after is a field to indicate a rollout should be performed
+	// after the specified time even if no changes have been made to the ControlPlane.
+	// Example: In the YAML the time can be specified in the RFC3339 format.
+	// To specify the rolloutAfter target as March 9, 2023, at 9 am UTC
+	// use "2023-03-09T09:00:00Z".
+	// +optional
+	After metav1.Time `json:"after,omitempty,omitzero"`
+}
+
 // ControlPlaneTopologyHealthCheck defines a MachineHealthCheck for control plane machines.
 // +kubebuilder:validation:MinProperties=1
 type ControlPlaneTopologyHealthCheck struct {
@@ -1107,6 +1123,15 @@ type MachineDeploymentTopologyMachineDeletionSpec struct {
 // MachineDeploymentTopologyRolloutSpec defines the rollout behavior.
 // +kubebuilder:validation:MinProperties=1
 type MachineDeploymentTopologyRolloutSpec struct {
+	// after is a field to indicate a rollout should be performed
+	// after the specified time even if no changes have been made to the
+	// MachineDeployment.
+	// Example: In the YAML the time can be specified in the RFC3339 format.
+	// To specify the rolloutAfter target as March 9, 2023, at 9 am UTC
+	// use "2023-03-09T09:00:00Z".
+	// +optional
+	After metav1.Time `json:"after,omitempty,omitzero"`
+
 	// strategy specifies how to roll out control plane Machines.
 	// +optional
 	Strategy MachineDeploymentTopologyRolloutStrategy `json:"strategy,omitempty,omitzero"`

api/core/v1beta2/cluster_types.go

@@ -67,6 +67,7 @@ repo or add an item to the agenda in the [Cluster API community meeting](https:/
 | [ControlPlane: replicas]                                             | No        | Mandatory if control plane has a notion of number of instances.                                                            |
 | [ControlPlane: version]                                              | No        | Mandatory if control plane allows direct management of the Kubernetes version in use; Mandatory for cluster class support. |
 | [ControlPlane: machines]                                             | No        | Mandatory if control plane instances are represented with a set of Cluster API Machines.                                   |
+| [ControlPlane: rolloutAfter]                                         | No        |                                                                                                                            |
 | [ControlPlane: initialization completed]                             | Yes       |                                                                                                                            |
 | [ControlPlane: in-place updates]                                     | No        | Only supported for control plane providers with control plane machines                                                     |
 | [ControlPlane: conditions]                                           | No        |                                                                                                                            |
@@ -598,6 +599,34 @@ can benefit from several Cluster API behaviours, for example:
 - Machine health checking
 - Machine drain and wait for volume detach during deletion
 
+### ControlPlane: rolloutAfter
+
+In case you are developing a control plane provider which supports scheduled rollout via
+the `rolloutAfter` field, following fields MUST be implemented in the ControlPlane `spec`.
+
+```go
+type FooControlPlaneSpec struct {
+    // rollout allows you to configure the behaviour of rolling updates to the control plane.
+    // +optional
+    Rollout FooControlPlaneRolloutSpec `json:"rollout,omitempty,omitzero"`
+	
+    // See other rules for more details about mandatory/optional fields in ControlPlane status.
+    // Other fields SHOULD be added based on the needs of your provider.
+}
+
+// +kubebuilder:validation:MinProperties=1
+type FooControlPlaneRolloutSpec struct {
+    // after is a field to indicate a rollout should be performed
+    // after the specified time even if no changes have been made to the
+    // FooControlPlane.
+    // Example: In the YAML the time can be specified in the RFC3339 format.
+    // To specify the rolloutAfter target as March 9, 2023, at 9 am UTC
+    // use "2023-03-09T09:00:00Z".
+    // +optional
+    After metav1.Time `json:"after,omitempty,omitzero"`
+}
+```
+
 ### ControlPlane: initialization completed
 
 Each ControlPlane MUST report when the Kubernetes control plane is initialized; usually a control plane is considered
@@ -934,6 +963,7 @@ is implemented in ControlPlane controllers:
 [ControlPlane: replicas]: #controlplane-replicas 
 [scale]: https://kubernetes.io/docs/tasks/extend-kubernetes/custom-resources/custom-resource-definitions/#subresources
 [ControlPlane: machines]: #controlplane-machines
+[ControlPlane: rolloutAfter]: #controlplane-rolloutafter
 [In place propagation of changes affecting Kubernetes objects only]: https://github.com/kubernetes-sigs/cluster-api/blob/main/docs/proposals/20221003-In-place-propagation-of-Kubernetes-objects-only-changes.md
 [ControlPlane: version]: #controlplane-version 
 [ControlPlane: initialization completed]: #controlplane-initialization-completed

api/core/v1beta2/zz_generated.deepcopy.go

@@ -45,6 +45,8 @@ Any feedback or contributions to improve following documentation is welcome!
 
 - A new, optional rule has been added to the control plane contract, defining what is required for implementing support 
   for taints.
+- A new, optional rule has been added to the control plane contract, defining what is required for implementing support
+  for rolloutAfter.
 
 ## Deprecation
 

api/core/v1beta2/zz_generated.openapi.go

@@ -433,6 +433,13 @@ func (g *generator) computeControlPlane(ctx context.Context, s *scope.Scope, inf
 		}
 	}
 
+	// If it is required to manage rolloutAfter for the control plane, set the corresponding field.
+	if !s.Blueprint.Topology.ControlPlane.Rollout.After.IsZero() {
+		if err := contract.ControlPlane().RolloutAfter().Set(controlPlane, s.Blueprint.Topology.ControlPlane.Rollout.After); err != nil {
+			return nil, errors.Wrapf(err, "failed to set %s in the ControlPlane object", contract.ControlPlane().RolloutAfter().Path())
+		}
+	}
+
 	// If it is required to manage the readinessGates for the control plane, set the corresponding field.
 	// NOTE: If readinessGates value from both Cluster and ClusterClass is nil, it is assumed that the control plane controller
 	// does not implement support for this field and the ControlPlane object is generated without readinessGates.
@@ -900,6 +907,7 @@ func (g *generator) computeMachineDeployment(ctx context.Context, s *scope.Scope
 	}
 	if !reflect.DeepEqual(machineDeploymentTopology.Rollout, clusterv1.MachineDeploymentTopologyRolloutSpec{}) {
 		rollout = clusterv1.MachineDeploymentRolloutSpec{
+			After: machineDeploymentTopology.Rollout.After,
 			Strategy: clusterv1.MachineDeploymentRolloutStrategy{
 				Type: machineDeploymentTopology.Rollout.Strategy.Type,
 				RollingUpdate: clusterv1.MachineDeploymentRolloutStrategyRollingUpdate{