Fix patching OpenstackMachine's immutable spec during reconcile

when the VM is vanished (cannot be fetched but existed at some
point)

controllers/openstackmachine_controller.go

@@ -439,12 +439,17 @@ func (r *OpenStackMachineReconciler) getOrCreate(logger logr.Logger, cluster *cl
 	}
 
 	if instanceStatus == nil {
-		instanceSpec := machineToInstanceSpec(openStackCluster, machine, openStackMachine, userData)
-		logger.Info("Machine does not exist, creating Machine", "name", openStackMachine.Name)
-		instanceStatus, err = computeService.CreateInstance(openStackMachine, openStackCluster, instanceSpec, cluster.Name)
-		if err != nil {
-			conditions.MarkFalse(openStackMachine, infrav1.InstanceReadyCondition, infrav1.InstanceCreateFailedReason, clusterv1.ConditionSeverityError, err.Error())
-			return nil, fmt.Errorf("create OpenStack instance: %w", err)
+		if openStackMachine.Spec.InstanceID != nil {
+			logger.Info("Not reconciling machine in failed state. The previously existing OpenStack instance is no longer available")
+			return nil, nil
+		} else {
+			instanceSpec := machineToInstanceSpec(openStackCluster, machine, openStackMachine, userData)
+			logger.Info("Machine does not exist, creating Machine", "name", openStackMachine.Name)
+			instanceStatus, err = computeService.CreateInstance(openStackMachine, openStackCluster, instanceSpec, cluster.Name)
+			if err != nil {
+				conditions.MarkFalse(openStackMachine, infrav1.InstanceReadyCondition, infrav1.InstanceCreateFailedReason, clusterv1.ConditionSeverityError, err.Error())
+				return nil, fmt.Errorf("create OpenStack instance: %w", err)
+			}
 		}
 	}