func UpdateExistingReplicationController(c client.Interface, oldRc *api.ReplicationController, namespace, newName, deploymentKey, deploymentValue string, out io.Writer) (*api.ReplicationController, error) {
	SetNextControllerAnnotation(oldRc, newName)
	if _, found := oldRc.Spec.Selector[deploymentKey]; !found {
		return AddDeploymentKeyToReplicationController(oldRc, c, deploymentKey, deploymentValue, namespace, out)
	} else {
		// If we didn't need to update the controller for the deployment key, we still need to write
		// the "next" controller.
		return c.ReplicationControllers(namespace).Update(oldRc)
	}
}
func deleteReplicationControllers(qingClient client.Interface, ns string) error {
	items, err := qingClient.ReplicationControllers(ns).List(labels.Everything())
	if err != nil {
		return err
	}
	for i := range items.Items {
		err := qingClient.ReplicationControllers(ns).Delete(items.Items[i].Name)
		if err != nil && !errors.IsNotFound(err) {
			return err
		}
	}
	return nil
}
func AddDeploymentKeyToReplicationController(oldRc *api.ReplicationController, client client.Interface, deploymentKey, deploymentValue, namespace string, out io.Writer) (*api.ReplicationController, error) {
	var err error
	// First, update the template label.  This ensures that any newly created pods will have the new label
	if oldRc, err = updateWithRetries(client.ReplicationControllers(namespace), oldRc, func(rc *api.ReplicationController) {
		if rc.Spec.Template.Labels == nil {
			rc.Spec.Template.Labels = map[string]string{}
		}
		rc.Spec.Template.Labels[deploymentKey] = deploymentValue
	}); err != nil {
		return nil, err
	}

	// Update all pods managed by the rc to have the new hash label, so they are correctly adopted
	// TODO: extract the code from the label command and re-use it here.
	podList, err := client.Pods(namespace).List(labels.SelectorFromSet(oldRc.Spec.Selector), fields.Everything())
	if err != nil {
		return nil, err
	}
	for ix := range podList.Items {
		pod := &podList.Items[ix]
		if pod.Labels == nil {
			pod.Labels = map[string]string{
				deploymentKey: deploymentValue,
			}
		} else {
			pod.Labels[deploymentKey] = deploymentValue
		}
		err = nil
		delay := 3
		for i := 0; i < MaxRetries; i++ {
			_, err = client.Pods(namespace).Update(pod)
			if err != nil {
				fmt.Fprintf(out, "Error updating pod (%v), retrying after %d seconds", err, delay)
				time.Sleep(time.Second * time.Duration(delay))
				delay *= delay
			} else {
				break
			}
		}
		if err != nil {
			return nil, err
		}
	}

	if oldRc.Spec.Selector == nil {
		oldRc.Spec.Selector = map[string]string{}
	}
	// Copy the old selector, so that we can scrub out any orphaned pods
	selectorCopy := map[string]string{}
	for k, v := range oldRc.Spec.Selector {
		selectorCopy[k] = v
	}
	oldRc.Spec.Selector[deploymentKey] = deploymentValue

	// Update the selector of the rc so it manages all the pods we updated above
	if oldRc, err = updateWithRetries(client.ReplicationControllers(namespace), oldRc, func(rc *api.ReplicationController) {
		rc.Spec.Selector[deploymentKey] = deploymentValue
	}); err != nil {
		return nil, err
	}

	// Clean up any orphaned pods that don't have the new label, this can happen if the rc manager
	// doesn't see the update to its pod template and creates a new pod with the old labels after
	// we've finished re-adopting existing pods to the rc.
	podList, err = client.Pods(namespace).List(labels.SelectorFromSet(selectorCopy), fields.Everything())
	for ix := range podList.Items {
		pod := &podList.Items[ix]
		if value, found := pod.Labels[deploymentKey]; !found || value != deploymentValue {
			if err := client.Pods(namespace).Delete(pod.Name, nil); err != nil {
				return nil, err
			}
		}
	}

	return oldRc, nil
}