Store hash to determine when pod spec changes

Comparing the desired pod spec to the current pod spec is not reliable as
the spec can be mutated by k8s e.g to add volume mount for a service account
or to add the default nodeselector from the namespace/cluster on OpenShift

Instead store a hash of the original pod spec and compare this to the hash
of the current desired pod spec to determine if the spec has changed.

Author: olliewalsh

apis/bases/client.openstack.org_openstackclients.yaml

@@ -82,6 +82,10 @@ spec:
                   - type
                   type: object
                 type: array
+              hash:
+                additionalProperties:
+                  type: string
+                type: object
               observedGeneration:
                 format: int64
                 type: integer

apis/client/v1beta1/openstackclient_types.go

@@ -68,6 +68,9 @@ type OpenStackClientStatus struct {
 
 	//ObservedGeneration - the most recent generation observed for this object.
 	ObservedGeneration int64 `json:"observedGeneration,omitempty"`
+
+	// Map of hashes to track e.g. pod spec
+	Hash map[string]string `json:"hash,omitempty"`
 }
 
 // +kubebuilder:object:root=true

apis/client/v1beta1/zz_generated.deepcopy.go

@@ -82,6 +82,10 @@ spec:
                   - type
                   type: object
                 type: array
+              hash:
+                additionalProperties:
+                  type: string
+                type: object
               observedGeneration:
                 format: int64
                 type: integer

config/crd/bases/client.openstack.org_openstackclients.yaml

@@ -307,16 +307,19 @@ func (r *OpenStackClientReconciler) Reconcile(ctx context.Context, req ctrl.Requ
 
 	spec := openstackclient.ClientPodSpec(ctx, instance, helper, configVarsHash)
 
+	podSpecHash, err := util.ObjectHash(spec)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+
+	podSpecHashName := "podSpec"
+
 	op, err := controllerutil.CreateOrPatch(ctx, r.Client, osclient, func() error {
 		isPodUpdate := !osclient.ObjectMeta.CreationTimestamp.IsZero()
-		if !isPodUpdate {
+		currentPodSpecHash := instance.Status.Hash[podSpecHashName]
+		if !isPodUpdate || currentPodSpecHash != podSpecHash {
 			osclient.Spec = spec
-		} else {
-			osclient.Spec.Containers[0].Env = spec.Containers[0].Env
-			osclient.Spec.NodeSelector = spec.NodeSelector
-			osclient.Spec.Containers[0].Image = instance.Spec.ContainerImage
 		}
-
 		osclient.Labels = util.MergeStringMaps(osclient.Labels, clientLabels)
 
 		err = controllerutil.SetControllerReference(instance, osclient, r.Scheme)
@@ -360,6 +363,8 @@ func (r *OpenStackClientReconciler) Reconcile(ctx context.Context, req ctrl.Requ
 		return ctrl.Result{}, err
 	}
 
+	instance.Status.Hash, _ = util.SetHash(instance.Status.Hash, podSpecHashName, podSpecHash)
+
 	if op != controllerutil.OperationResultNone {
 		util.LogForObject(
 			helper,