OpenStack support in CPMS

docs/user/failure-domains.md

@@ -83,3 +83,16 @@ An Azure failure domain will look something like the example below:
 ```yaml
 - zone: "<zone>"
 ```
+
+## OpenStack
+
+On OpenStack, the failure domains represented in the control plane machine set can be considered analogous to the
+OpenStack availability zones (for Nova and Cinder).
+
+An OpenStack failure domain will look something like the example below:
+```yaml
+- computeAvailabilityZone: "<zone>"
+  storageAvailabilityZone: "<zone>"
+```
+
+They are both optional and also can be set alone.

docs/user/installation.md

@@ -238,3 +238,31 @@ failureDomains:
 
 > Note: The `targetPools` field may not be set on the GCP providerSpec. This field is required for control
 plane machines and you should populate this on both the Machine and the ControlPlaneMachineSet resource specs.
+
+#### Configuring a control plane machine set on OpenStack
+
+Two fields are supported for now: `computeAvailabilityZone` (instance AZ) and `storageAvailabilityZone` (root volume AZ).
+Gather the existing control plane machines and note the value of the zones of each if they exist.
+Aside from these fields, the remaining in spec the machines should be identical.
+
+Copy the value from one of the machines into the `providerSpec.value` (6) on the example above.
+Remove the AZ fields from the `providerSpec.value` once you have done that.
+
+For each AZ you have in the cluster (normally 3), configure a failure domain like below:
+```yaml
+- computeAvailabilityZone: "<zone>"
+  storageAvailabilityZone: "<zone>"
+```
+
+With these zones, the complete `failureDomains` (3 and 4) on the example above should look something like below:
+```yaml
+failureDomains:
+  platform: OpenStack
+  openstack:
+  - computeAvailabilityZone: "us-central1-a"
+    storageAvailabilityZone: "us-central1-a"
+  - computeAvailabilityZone: "us-central1-b"
+    storageAvailabilityZone: "us-central1-b"
+  - computeAvailabilityZone: "us-central1-c"
+    storageAvailabilityZone: "us-central1-c"
+```

pkg/controllers/controlplanemachinesetgenerator/controller.go

@@ -210,6 +210,8 @@ func (r *ControlPlaneMachineSetGeneratorReconciler) reconcile(ctx context.Contex
 }
 
 // generateControlPlaneMachineSet generates a control plane machine set based on the current cluster state.
+//
+//nolint:cyclop
 func (r *ControlPlaneMachineSetGeneratorReconciler) generateControlPlaneMachineSet(logger logr.Logger,
 	platformType configv1.PlatformType, machines []machinev1beta1.Machine, machineSets []machinev1beta1.MachineSet) (*machinev1.ControlPlaneMachineSet, error) {
 	var (
@@ -233,6 +235,11 @@ func (r *ControlPlaneMachineSetGeneratorReconciler) generateControlPlaneMachineS
 		if err != nil {
 			return nil, fmt.Errorf("unable to generate control plane machine set spec: %w", err)
 		}
+	case configv1.OpenStackPlatformType:
+		cpmsSpecApplyConfig, err = generateControlPlaneMachineSetOpenStackSpec(machines, machineSets)
+		if err != nil {
+			return nil, fmt.Errorf("unable to generate control plane machine set spec: %w", err)
+		}
 	default:
 		logger.V(1).WithValues("platform", platformType).Info(unsupportedPlatform)
 		return nil, errUnsupportedPlatform