func CreateNewControllerFromCurrentController(c client.Interface, codec runtime.Codec, cfg *NewControllerConfig) (*api.ReplicationController, error) {
	containerIndex := 0
	// load the old RC into the "new" RC
	newRc, err := c.ReplicationControllers(cfg.Namespace).Get(cfg.OldName)
	if err != nil {
		return nil, err
	}

	if len(cfg.Container) != 0 {
		containerFound := false

		for i, c := range newRc.Spec.Template.Spec.Containers {
			if c.Name == cfg.Container {
				containerIndex = i
				containerFound = true
				break
			}
		}

		if !containerFound {
			return nil, fmt.Errorf("container %s not found in pod", cfg.Container)
		}
	}

	if len(newRc.Spec.Template.Spec.Containers) > 1 && len(cfg.Container) == 0 {
		return nil, goerrors.New("Must specify container to update when updating a multi-container pod")
	}

	if len(newRc.Spec.Template.Spec.Containers) == 0 {
		return nil, goerrors.New(fmt.Sprintf("Pod has no containers! (%v)", newRc))
	}
	newRc.Spec.Template.Spec.Containers[containerIndex].Image = cfg.Image
	if len(cfg.PullPolicy) != 0 {
		newRc.Spec.Template.Spec.Containers[containerIndex].ImagePullPolicy = cfg.PullPolicy
	}

	newHash, err := api.HashObject(newRc, codec)
	if err != nil {
		return nil, err
	}

	if len(cfg.NewName) == 0 {
		cfg.NewName = fmt.Sprintf("%s-%s", newRc.Name, newHash)
	}
	newRc.Name = cfg.NewName

	newRc.Spec.Selector[cfg.DeploymentKey] = newHash
	newRc.Spec.Template.Labels[cfg.DeploymentKey] = newHash
	// Clear resource version after hashing so that identical updates get different hashes.
	newRc.ResourceVersion = ""
	return newRc, nil
}
func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []string, options *RollingUpdateOptions) error {
	if len(os.Args) > 1 && os.Args[1] == "rollingupdate" {
		printDeprecationWarning("rolling-update", "rollingupdate")
	}
	err := validateArguments(cmd, options.Filenames, args)
	if err != nil {
		return err
	}

	deploymentKey := cmdutil.GetFlagString(cmd, "deployment-label-key")
	filename := ""
	image := cmdutil.GetFlagString(cmd, "image")
	pullPolicy := cmdutil.GetFlagString(cmd, "image-pull-policy")
	oldName := args[0]
	rollback := cmdutil.GetFlagBool(cmd, "rollback")
	period := cmdutil.GetFlagDuration(cmd, "update-period")
	interval := cmdutil.GetFlagDuration(cmd, "poll-interval")
	timeout := cmdutil.GetFlagDuration(cmd, "timeout")
	dryrun := cmdutil.GetDryRunFlag(cmd)
	outputFormat := cmdutil.GetFlagString(cmd, "output")
	container := cmdutil.GetFlagString(cmd, "container")

	if len(options.Filenames) > 0 {
		filename = options.Filenames[0]
	}

	cmdNamespace, enforceNamespace, err := f.DefaultNamespace()
	if err != nil {
		return err
	}

	client, err := f.Client()
	if err != nil {
		return err
	}

	var newRc *api.ReplicationController
	// fetch rc
	oldRc, err := client.ReplicationControllers(cmdNamespace).Get(oldName)
	if err != nil {
		if !errors.IsNotFound(err) || len(image) == 0 || len(args) > 1 {
			return err
		}
		// We're in the middle of a rename, look for an RC with a source annotation of oldName
		newRc, err := kubectl.FindSourceController(client, cmdNamespace, oldName)
		if err != nil {
			return err
		}
		return kubectl.Rename(client, newRc, oldName)
	}

	var keepOldName bool
	var replicasDefaulted bool

	mapper, typer := f.Object(cmdutil.GetIncludeThirdPartyAPIs(cmd))

	if len(filename) != 0 {
		schema, err := f.Validator(cmdutil.GetFlagBool(cmd, "validate"), cmdutil.GetFlagString(cmd, "schema-cache-dir"))
		if err != nil {
			return err
		}

		request := resource.NewBuilder(mapper, typer, resource.ClientMapperFunc(f.ClientForMapping), f.Decoder(true)).
			Schema(schema).
			NamespaceParam(cmdNamespace).DefaultNamespace().
			FilenameParam(enforceNamespace, false, filename).
			Do()
		obj, err := request.Object()
		if err != nil {
			return err
		}
		var ok bool
		// Handle filename input from stdin. The resource builder always returns an api.List
		// when creating resource(s) from a stream.
		if list, ok := obj.(*api.List); ok {
			if len(list.Items) > 1 {
				return cmdutil.UsageError(cmd, "%s specifies multiple items", filename)
			}
			obj = list.Items[0]
		}
		newRc, ok = obj.(*api.ReplicationController)
		if !ok {
			if gvks, _, err := typer.ObjectKinds(obj); err == nil {
				return cmdutil.UsageError(cmd, "%s contains a %v not a ReplicationController", filename, gvks[0])
			}
			glog.V(4).Infof("Object %#v is not a ReplicationController", obj)
			return cmdutil.UsageError(cmd, "%s does not specify a valid ReplicationController", filename)
		}
		infos, err := request.Infos()
		if err != nil || len(infos) != 1 {
			glog.V(2).Infof("was not able to recover adequate information to discover if .spec.replicas was defaulted")
		} else {
			replicasDefaulted = isReplicasDefaulted(infos[0])
		}
	}
	// If the --image option is specified, we need to create a new rc with at least one different selector
	// than the old rc. This selector is the hash of the rc, with a suffix to provide uniqueness for
	// same-image updates.
	if len(image) != 0 {
		codec := api.Codecs.LegacyCodec(client.APIVersion())
		keepOldName = len(args) == 1
		newName := findNewName(args, oldRc)
		if newRc, err = kubectl.LoadExistingNextReplicationController(client, cmdNamespace, newName); err != nil {
			return err
		}
		if newRc != nil {
			if inProgressImage := newRc.Spec.Template.Spec.Containers[0].Image; inProgressImage != image {
				return cmdutil.UsageError(cmd, "Found existing in-progress update to image (%s).\nEither continue in-progress update with --image=%s or rollback with --rollback", inProgressImage, inProgressImage)
			}
			fmt.Fprintf(out, "Found existing update in progress (%s), resuming.\n", newRc.Name)
		} else {
			config := &kubectl.NewControllerConfig{
				Namespace:     cmdNamespace,
				OldName:       oldName,
				NewName:       newName,
				Image:         image,
				Container:     container,
				DeploymentKey: deploymentKey,
			}
			if oldRc.Spec.Template.Spec.Containers[0].Image == image {
				if len(pullPolicy) == 0 {
					return cmdutil.UsageError(cmd, "--image-pull-policy (Always|Never|IfNotPresent) must be provided when --image is the same as existing container image")
				}
				config.PullPolicy = api.PullPolicy(pullPolicy)
			}
			newRc, err = kubectl.CreateNewControllerFromCurrentController(client, codec, config)
			if err != nil {
				return err
			}
		}
		// Update the existing replication controller with pointers to the 'next' controller
		// and adding the <deploymentKey> label if necessary to distinguish it from the 'next' controller.
		oldHash, err := api.HashObject(oldRc, codec)
		if err != nil {
			return err
		}
		// If new image is same as old, the hash may not be distinct, so add a suffix.
		oldHash += "-orig"
		oldRc, err = kubectl.UpdateExistingReplicationController(client, oldRc, cmdNamespace, newRc.Name, deploymentKey, oldHash, out)
		if err != nil {
			return err
		}
	}

	if rollback {
		keepOldName = len(args) == 1
		newName := findNewName(args, oldRc)
		if newRc, err = kubectl.LoadExistingNextReplicationController(client, cmdNamespace, newName); err != nil {
			return err
		}

		if newRc == nil {
			return cmdutil.UsageError(cmd, "Could not find %s to rollback.\n", newName)
		}
	}

	if oldName == newRc.Name {
		return cmdutil.UsageError(cmd, "%s cannot have the same name as the existing ReplicationController %s",
			filename, oldName)
	}

	updater := kubectl.NewRollingUpdater(newRc.Namespace, client)

	// To successfully pull off a rolling update the new and old rc have to differ
	// by at least one selector. Every new pod should have the selector and every
	// old pod should not have the selector.
	var hasLabel bool
	for key, oldValue := range oldRc.Spec.Selector {
		if newValue, ok := newRc.Spec.Selector[key]; ok && newValue != oldValue {
			hasLabel = true
			break
		}
	}
	if !hasLabel {
		return cmdutil.UsageError(cmd, "%s must specify a matching key with non-equal value in Selector for %s",
			filename, oldName)
	}
	// TODO: handle scales during rolling update
	if replicasDefaulted {
		newRc.Spec.Replicas = oldRc.Spec.Replicas
	}
	if dryrun {
		oldRcData := &bytes.Buffer{}
		newRcData := &bytes.Buffer{}
		if outputFormat == "" {
			oldRcData.WriteString(oldRc.Name)
			newRcData.WriteString(newRc.Name)
		} else {
			if err := f.PrintObject(cmd, mapper, oldRc, oldRcData); err != nil {
				return err
			}
			if err := f.PrintObject(cmd, mapper, newRc, newRcData); err != nil {
				return err
			}
		}
		fmt.Fprintf(out, "Rolling from:\n%s\nTo:\n%s\n", string(oldRcData.Bytes()), string(newRcData.Bytes()))
		return nil
	}
	updateCleanupPolicy := kubectl.DeleteRollingUpdateCleanupPolicy
	if keepOldName {
		updateCleanupPolicy = kubectl.RenameRollingUpdateCleanupPolicy
	}
	config := &kubectl.RollingUpdaterConfig{
		Out:            out,
		OldRc:          oldRc,
		NewRc:          newRc,
		UpdatePeriod:   period,
		Interval:       interval,
		Timeout:        timeout,
		CleanupPolicy:  updateCleanupPolicy,
		MaxUnavailable: intstr.FromInt(0),
		MaxSurge:       intstr.FromInt(1),
	}
	if rollback {
		err = kubectl.AbortRollingUpdate(config)
		if err != nil {
			return err
		}
		client.ReplicationControllers(config.NewRc.Namespace).Update(config.NewRc)
	}
	err = updater.Update(config)
	if err != nil {
		return err
	}

	message := "rolling updated"
	if keepOldName {
		newRc.Name = oldName
	} else {
		message = fmt.Sprintf("rolling updated to %q", newRc.Name)
	}
	newRc, err = client.ReplicationControllers(cmdNamespace).Get(newRc.Name)
	if err != nil {
		return err
	}
	if outputFormat != "" {
		return f.PrintObject(cmd, mapper, newRc, out)
	}
	kinds, _, err := api.Scheme.ObjectKinds(newRc)
	if err != nil {
		return err
	}
	_, res := meta.KindToResource(kinds[0])
	cmdutil.PrintSuccess(mapper, false, out, res.Resource, oldName, message)
	return nil
}