Patch bundle deployment status in drift controller (#3032)

This prevents that new controller from making heavy-handed updates to
bundle deployment statuses, reducing the risk of conflicts, as already
done for the bundle deployment reconciler.

internal/cmd/agent/controller/drift_controller.go

@@ -13,9 +13,7 @@ import (
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	"k8s.io/apimachinery/pkg/runtime"
-	"k8s.io/apimachinery/pkg/types"
 	errutil "k8s.io/apimachinery/pkg/util/errors"
-	"k8s.io/client-go/util/retry"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/event"
@@ -65,6 +63,8 @@ func (r *DriftReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl
 		return ctrl.Result{}, err
 	}
 
+	orig := bd.DeepCopy()
+
 	if bd.Spec.Paused {
 		logger.V(1).Info("Bundle paused, clearing drift detection")
 		err := r.DriftDetect.Clear(req.String())
@@ -106,7 +106,7 @@ func (r *DriftReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl
 
 	// final status update
 	logger.V(1).Info("Reconcile finished, updating the bundledeployment status")
-	err = r.updateStatus(ctx, req.NamespacedName, bd.Status)
+	err = r.updateStatus(ctx, orig, bd)
 	if apierrors.IsNotFound(err) {
 		merr = append(merr, fmt.Errorf("bundledeployment has been deleted: %w", err))
 	} else if err != nil {
@@ -116,14 +116,11 @@ func (r *DriftReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl
 	return ctrl.Result{}, errutil.NewAggregate(merr)
 }
 
-func (r *DriftReconciler) updateStatus(ctx context.Context, req types.NamespacedName, status fleetv1.BundleDeploymentStatus) error {
-	return retry.RetryOnConflict(DefaultRetry, func() error {
-		newBD := &fleetv1.BundleDeployment{}
-		err := r.Get(ctx, req, newBD)
-		if err != nil {
-			return err
-		}
-		newBD.Status = status
-		return r.Status().Update(ctx, newBD)
-	})
+func (r *DriftReconciler) updateStatus(
+	ctx context.Context,
+	orig *fleetv1.BundleDeployment,
+	obj *fleetv1.BundleDeployment,
+) error {
+	statusPatch := client.MergeFrom(orig)
+	return r.Status().Patch(ctx, obj, statusPatch)
 }