From a71a77e162cfa028f840ae3a87cfdd02f674a109 Mon Sep 17 00:00:00 2001
From: Matt Pryor <matt@stackhpc.com>
Date: Mon, 1 Aug 2022 17:26:33 +0100
Subject: [PATCH] Allow for omiting AZ from control plane nodes

---
 api/v1alpha6/openstackcluster_types.go          |  4 ++++
 ...ture.cluster.x-k8s.io_openstackclusters.yaml |  5 +++++
 ...ster.x-k8s.io_openstackclustertemplates.yaml |  5 +++++
 controllers/openstackcluster_controller.go      | 17 ++++++-----------
 4 files changed, 20 insertions(+), 11 deletions(-)

diff --git a/api/v1alpha6/openstackcluster_types.go b/api/v1alpha6/openstackcluster_types.go
index 189544ab38..907602e66a 100644
--- a/api/v1alpha6/openstackcluster_types.go
+++ b/api/v1alpha6/openstackcluster_types.go
@@ -126,6 +126,10 @@ type OpenStackClusterSpec struct {
 	// ControlPlaneAvailabilityZones is the az to deploy control plane to
 	ControlPlaneAvailabilityZones []string `json:"controlPlaneAvailabilityZones,omitempty"`
 
+	// Indicates whether to omit the az for control plane nodes, allowing the Nova scheduler
+	// to make a decision on which az to use based on other scheduling constraints
+	ControlPlaneOmitAvailabilityZone bool `json:"controlPlaneOmitAvailabilityZone,omitempty"`
+
 	// Bastion is the OpenStack instance to login the nodes
 	//
 	// As a rolling update is not ideal during a bastion host session, we
diff --git a/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclusters.yaml b/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclusters.yaml
index 07f1d45f78..fef03fe59d 100644
--- a/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclusters.yaml
+++ b/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclusters.yaml
@@ -4724,6 +4724,11 @@ spec:
                 - host
                 - port
                 type: object
+              controlPlaneOmitAvailabilityZone:
+                description: Indicates whether to omit the az for control plane nodes,
+                  allowing the Nova scheduler to make a decision on which az to use
+                  based on other scheduling constraints
+                type: boolean
               disableAPIServerFloatingIP:
                 description: DisableAPIServerFloatingIP determines whether or not
                   to attempt to attach a floating IP to the API server. This allows
diff --git a/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclustertemplates.yaml b/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclustertemplates.yaml
index 14cea0ef6e..4be92420fe 100644
--- a/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclustertemplates.yaml
+++ b/config/crd/bases/infrastructure.cluster.x-k8s.io_openstackclustertemplates.yaml
@@ -1962,6 +1962,11 @@ spec:
                         - host
                         - port
                         type: object
+                      controlPlaneOmitAvailabilityZone:
+                        description: Indicates whether to omit the az for control
+                          plane nodes, allowing the Nova scheduler to make a decision
+                          on which az to use based on other scheduling constraints
+                        type: boolean
                       disableAPIServerFloatingIP:
                         description: DisableAPIServerFloatingIP determines whether
                           or not to attempt to attach a floating IP to the API server.
diff --git a/controllers/openstackcluster_controller.go b/controllers/openstackcluster_controller.go
index f3ed104b14..e8bbec977c 100644
--- a/controllers/openstackcluster_controller.go
+++ b/controllers/openstackcluster_controller.go
@@ -280,21 +280,16 @@ func reconcileNormal(ctx context.Context, scope *scope.Scope, patchHelper *patch
 		return ctrl.Result{}, err
 	}
 
-	// Create a new list to remove any Availability
-	// Zones that have been removed from OpenStack
+	// Create a new list in case any AZs have been removed from OpenStack
 	openStackCluster.Status.FailureDomains = make(clusterv1.FailureDomains)
 	for _, az := range availabilityZones {
-		found := true
-		// If Az given, then check whether it's in the allow list
-		// If no Az given, then by default put into allow list
+		// By default, the AZ is used or not used for control plane nodes depending on the flag
+		found := !openStackCluster.Spec.ControlPlaneOmitAvailabilityZone
+		// If explicit AZs for control plane nodes are given, they override the value
 		if len(openStackCluster.Spec.ControlPlaneAvailabilityZones) > 0 {
-			if contains(openStackCluster.Spec.ControlPlaneAvailabilityZones, az.ZoneName) {
-				found = true
-			} else {
-				found = false
-			}
+			found = contains(openStackCluster.Spec.ControlPlaneAvailabilityZones, az.ZoneName)
 		}
-
+		// Add the AZ object to the failure domains for the cluster
 		openStackCluster.Status.FailureDomains[az.ZoneName] = clusterv1.FailureDomainSpec{
 			ControlPlane: found,
 		}