Support recovery from in the middle of a rename.

pkg/api/helpers.go

@@ -17,12 +17,15 @@ limitations under the License.
 package api
 
 import (
+	"crypto/md5"
+	"fmt"
 	"reflect"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/resource"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/conversion"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/fields"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 
 	"github.com/davecgh/go-spew/spew"
@@ -130,3 +133,11 @@ func AddToNodeAddresses(addresses *[]NodeAddress, addAddresses ...NodeAddress) {
 		}
 	}
 }
+
+func HashObject(obj runtime.Object, codec runtime.Codec) (string, error) {
+	data, err := codec.Encode(obj)
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("%x", md5.Sum(data)), nil
+}

pkg/kubectl/cmd/rollingupdate.go

@@ -18,23 +18,15 @@ package cmd
 
 import (
 	"bytes"
-	"crypto/md5"
-	"errors"
 	"fmt"
 	"io"
 	"os"
-	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
-	apierrors "github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/fields"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl"
 	cmdutil "github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/cmd/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/kubectl/resource"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/wait"
 	"github.com/spf13/cobra"
 )
 
@@ -131,16 +123,26 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 		return err
 	}
 
+	updaterClient := kubectl.NewRollingUpdaterClient(client)
+
+	var newRc *api.ReplicationController
 	// fetch rc
 	oldRc, err := client.ReplicationControllers(cmdNamespace).Get(oldName)
 	if err != nil {
-		return err
+		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(updaterClient, cmdNamespace, oldName)
+		if err != nil {
+			return err
+		}
+		return kubectl.Rename(kubectl.NewRollingUpdaterClient(client), newRc, oldName)
 	}
 
-	keepOldName := false
+	var keepOldName bool
 
 	mapper, typer := f.Object()
-	var newRc *api.ReplicationController
 
 	if len(filename) != 0 {
 		obj, err := resource.NewBuilder(mapper, typer, f.ClientMapperForCommand()).
@@ -161,73 +163,36 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	// than the old rc. This selector is the hash of the rc, which will differ because the new rc has a
 	// different image.
 	if len(image) != 0 {
-		var newName string
-		var err error
-
-		if len(args) >= 2 {
-			newName = args[1]
-		} else {
-			newName, _ = kubectl.GetNextControllerAnnotation(oldRc)
-		}
-
-		if len(newName) > 0 {
-			newRc, err = client.ReplicationControllers(cmdNamespace).Get(newName)
-			if err != nil {
-				if !apierrors.IsNotFound(err) {
-					return err
-				} else {
-					newRc = nil
-				}
-			} else {
-				fmt.Fprint(out, "Found existing update in progress (%s), resuming.\n", newName)
-			}
+		keepOldName = len(args) == 1
+		newName := findNewName(args, oldRc)
+		if newRc, err = kubectl.LoadExistingNextReplicationController(client, cmdNamespace, newName); err != nil {
+			return err
 		}
-		if newRc == nil {
-			// load the old RC into the "new" RC
-			if newRc, err = client.ReplicationControllers(cmdNamespace).Get(oldName); err != nil {
-				return err
-			}
-
-			if len(newRc.Spec.Template.Spec.Containers) > 1 {
-				// TODO: support multi-container image update.
-				return errors.New("Image update is not supported for multi-container pods")
-			}
-			if len(newRc.Spec.Template.Spec.Containers) == 0 {
-				return cmdutil.UsageError(cmd, "Pod has no containers! (%v)", newRc)
-			}
-			newRc.Spec.Template.Spec.Containers[0].Image = image
-
-			newHash, err := hashObject(newRc, client.Codec)
+		if newRc != nil {
+			fmt.Fprintf(out, "Found existing update in progress (%s), resuming.\n", newRc.Name)
+		} else {
+			newRc, err = kubectl.CreateNewControllerFromCurrentController(client, cmdNamespace, oldName, newName, image, deploymentKey)
 			if err != nil {
 				return err
 			}
-
-			if len(newName) == 0 {
-				keepOldName = true
-				newName = fmt.Sprintf("%s-%s", newRc.Name, newHash)
-			}
-			newRc.Name = newName
-
-			newRc.Spec.Selector[deploymentKey] = newHash
-			newRc.Spec.Template.Labels[deploymentKey] = newHash
-			// Clear resource version after hashing so that identical updates get different hashes.
-			newRc.ResourceVersion = ""
-
-			kubectl.SetNextControllerAnnotation(oldRc, newName)
-			if _, found := oldRc.Spec.Selector[deploymentKey]; !found {
-				if oldRc, err = addDeploymentKeyToReplicationController(oldRc, client, deploymentKey, cmdNamespace, out); 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, client.Codec)
+		if err != nil {
+			return err
+		}
+		oldRc, err = kubectl.UpdateExistingReplicationController(client, oldRc, cmdNamespace, newRc.Name, deploymentKey, oldHash, out)
+		if err != nil {
+			return err
 		}
 	}
-	newName := newRc.Name
-	if oldName == 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, kubectl.NewRollingUpdaterClient(client))
+	updater := kubectl.NewRollingUpdater(newRc.Namespace, updaterClient)
 
 	// 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
@@ -284,124 +249,18 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	if keepOldName {
 		fmt.Fprintf(out, "%s\n", oldName)
 	} else {
-		fmt.Fprintf(out, "%s\n", newName)
+		fmt.Fprintf(out, "%s\n", newRc.Name)
 	}
 	return nil
 }
 
-func hashObject(obj runtime.Object, codec runtime.Codec) (string, error) {
-	data, err := codec.Encode(obj)
-	if err != nil {
-		return "", err
-	}
-	return fmt.Sprintf("%x", md5.Sum(data)), nil
-}
-
-const MaxRetries = 3
-
-type updateFunc func(controller *api.ReplicationController)
-
-// updateWithRetries updates applies the given rc as an update.
-func updateWithRetries(rcClient client.ReplicationControllerInterface, rc *api.ReplicationController, applyUpdate updateFunc) (*api.ReplicationController, error) {
-	// Each update could take ~100ms, so give it 0.5 second
-	var err error
-	oldRc := rc
-	err = wait.Poll(10*time.Millisecond, 500*time.Millisecond, func() (bool, error) {
-		// Apply the update, then attempt to push it to the apiserver.
-		applyUpdate(rc)
-		if rc, err = rcClient.Update(rc); err == nil {
-			// rc contains the latest controller post update
-			return true, nil
-		}
-		// Update the controller with the latest resource version, if the update failed we
-		// can't trust rc so use oldRc.Name.
-		if rc, err = rcClient.Get(oldRc.Name); err != nil {
-			// The Get failed: Value in rc cannot be trusted.
-			rc = oldRc
-		}
-		// The Get passed: rc contains the latest controller, expect a poll for the update.
-		return false, nil
-	})
-	// If the error is non-nil the returned controller cannot be trusted, if it is nil, the returned
-	// controller contains the applied update.
-	return rc, err
-}
-
-func addDeploymentKeyToReplicationController(oldRc *api.ReplicationController, client *client.Client, deploymentKey, namespace string, out io.Writer) (*api.ReplicationController, error) {
-	oldHash, err := hashObject(oldRc, client.Codec)
-	if err != nil {
-		return nil, err
-	}
-	// First, update the template label.  This ensures that any newly created pods will have the new label
-	if oldRc.Spec.Template.Labels == nil {
-		oldRc.Spec.Template.Labels = map[string]string{}
-	}
-	if oldRc, err = updateWithRetries(client.ReplicationControllers(namespace), oldRc, func(rc *api.ReplicationController) {
-		rc.Spec.Template.Labels[deploymentKey] = oldHash
-	}); 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: oldHash,
-			}
-		} else {
-			pod.Labels[deploymentKey] = oldHash
-		}
-		err = nil
-		delay := 3
-		for i := 0; i < MaxRetries; i++ {
-			_, err = client.Pods(namespace).Update(pod)
-			if err != nil {
-				fmt.Fprint(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
-		}
+func findNewName(args []string, oldRc *api.ReplicationController) string {
+	if len(args) >= 2 {
+		return args[1]
 	}
-
-	if oldRc.Spec.Selector == nil {
-		oldRc.Spec.Selector = map[string]string{}
+	if oldRc != nil {
+		newName, _ := kubectl.GetNextControllerAnnotation(oldRc)
+		return newName
 	}
-	// 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
-	}
-
-	// 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] = oldHash
-	}); 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 != oldHash {
-			if err := client.Pods(namespace).Delete(pod.Name, nil); err != nil {
-				return nil, err
-			}
-		}
-	}
-
-	return oldRc, nil
+	return ""
 }

pkg/kubectl/cmd/rollingupdate_test.go

@@ -18,16 +18,7 @@ package cmd
 
 import (
 	"bytes"
-	"io/ioutil"
-	"net/http"
-	"reflect"
 	"testing"
-
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 )
 
 func TestValidateArgs(t *testing.T) {
@@ -98,192 +89,3 @@ func TestValidateArgs(t *testing.T) {
 		}
 	}
 }
-
-func TestAddDeploymentHash(t *testing.T) {
-	buf := &bytes.Buffer{}
-	f, tf, codec := NewAPIFactory()
-	rc := &api.ReplicationController{
-		ObjectMeta: api.ObjectMeta{Name: "rc"},
-		Spec: api.ReplicationControllerSpec{
-			Selector: map[string]string{
-				"foo": "bar",
-			},
-			Template: &api.PodTemplateSpec{
-				ObjectMeta: api.ObjectMeta{
-					Labels: map[string]string{
-						"foo": "bar",
-					},
-				},
-			},
-		},
-	}
-
-	podList := &api.PodList{
-		Items: []api.Pod{
-			{ObjectMeta: api.ObjectMeta{Name: "foo"}},
-			{ObjectMeta: api.ObjectMeta{Name: "bar"}},
-			{ObjectMeta: api.ObjectMeta{Name: "baz"}},
-		},
-	}
-
-	seen := util.StringSet{}
-	updatedRc := false
-	tf.Client = &client.FakeRESTClient{
-		Codec: codec,
-		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
-			switch p, m := req.URL.Path, req.Method; {
-			case p == "/api/v1beta3/namespaces/default/pods" && m == "GET":
-				if req.URL.RawQuery != "labelSelector=foo%3Dbar" {
-					t.Errorf("Unexpected query string: %s", req.URL.RawQuery)
-				}
-				return &http.Response{StatusCode: 200, Body: objBody(codec, podList)}, nil
-			case p == "/api/v1beta3/namespaces/default/pods/foo" && m == "PUT":
-				seen.Insert("foo")
-				obj := readOrDie(t, req, codec)
-				podList.Items[0] = *(obj.(*api.Pod))
-				return &http.Response{StatusCode: 200, Body: objBody(codec, &podList.Items[0])}, nil
-			case p == "/api/v1beta3/namespaces/default/pods/bar" && m == "PUT":
-				seen.Insert("bar")
-				obj := readOrDie(t, req, codec)
-				podList.Items[1] = *(obj.(*api.Pod))
-				return &http.Response{StatusCode: 200, Body: objBody(codec, &podList.Items[1])}, nil
-			case p == "/api/v1beta3/namespaces/default/pods/baz" && m == "PUT":
-				seen.Insert("baz")
-				obj := readOrDie(t, req, codec)
-				podList.Items[2] = *(obj.(*api.Pod))
-				return &http.Response{StatusCode: 200, Body: objBody(codec, &podList.Items[2])}, nil
-			case p == "/api/v1beta3/namespaces/default/replicationcontrollers/rc" && m == "PUT":
-				updatedRc = true
-				return &http.Response{StatusCode: 200, Body: objBody(codec, rc)}, nil
-			default:
-				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
-				return nil, nil
-			}
-		}),
-	}
-	tf.ClientConfig = &client.Config{Version: latest.Version}
-	tf.Namespace = "test"
-
-	client, err := f.Client()
-	if err != nil {
-		t.Errorf("unexpected error: %v", err)
-		t.Fail()
-		return
-	}
-
-	if _, err := addDeploymentKeyToReplicationController(rc, client, "hash", api.NamespaceDefault, buf); err != nil {
-		t.Errorf("unexpected error: %v", err)
-	}
-	for _, pod := range podList.Items {
-		if !seen.Has(pod.Name) {
-			t.Errorf("Missing update for pod: %s", pod.Name)
-		}
-	}
-	if !updatedRc {
-		t.Errorf("Failed to update replication controller with new labels")
-	}
-}
-
-func TestUpdateWithRetries(t *testing.T) {
-	f, tf, codec := NewAPIFactory()
-	rc := &api.ReplicationController{
-		ObjectMeta: api.ObjectMeta{Name: "rc",
-			Labels: map[string]string{
-				"foo": "bar",
-			},
-		},
-		Spec: api.ReplicationControllerSpec{
-			Selector: map[string]string{
-				"foo": "bar",
-			},
-			Template: &api.PodTemplateSpec{
-				ObjectMeta: api.ObjectMeta{
-					Labels: map[string]string{
-						"foo": "bar",
-					},
-				},
-				Spec: api.PodSpec{
-					RestartPolicy: api.RestartPolicyAlways,
-					DNSPolicy:     api.DNSClusterFirst,
-				},
-			},
-		},
-	}
-
-	// Test end to end updating of the rc with retries. Essentially make sure the update handler
-	// sees the right updates, failures in update/get are handled properly, and that the updated
-	// rc with new resource version is returned to the caller. Without any of these rollingupdate
-	// will fail cryptically.
-	newRc := *rc
-	newRc.ResourceVersion = "2"
-	newRc.Spec.Selector["baz"] = "foobar"
-	updates := []*http.Response{
-		{StatusCode: 500, Body: objBody(codec, &api.ReplicationController{})},
-		{StatusCode: 500, Body: objBody(codec, &api.ReplicationController{})},
-		{StatusCode: 200, Body: objBody(codec, &newRc)},
-	}
-	gets := []*http.Response{
-		{StatusCode: 500, Body: objBody(codec, &api.ReplicationController{})},
-		{StatusCode: 200, Body: objBody(codec, rc)},
-	}
-	tf.Client = &client.FakeRESTClient{
-		Codec: codec,
-		Client: client.HTTPClientFunc(func(req *http.Request) (*http.Response, error) {
-			switch p, m := req.URL.Path, req.Method; {
-			case p == "/api/v1beta3/namespaces/default/replicationcontrollers/rc" && m == "PUT":
-				update := updates[0]
-				updates = updates[1:]
-				// We should always get an update with a valid rc even when the get fails. The rc should always
-				// contain the update.
-				if c, ok := readOrDie(t, req, codec).(*api.ReplicationController); !ok || !reflect.DeepEqual(rc, c) {
-					t.Errorf("Unexpected update body, got %+v expected %+v", c, rc)
-				} else if sel, ok := c.Spec.Selector["baz"]; !ok || sel != "foobar" {
-					t.Errorf("Expected selector label update, got %+v", c.Spec.Selector)
-				} else {
-					delete(c.Spec.Selector, "baz")
-				}
-				return update, nil
-			case p == "/api/v1beta3/namespaces/default/replicationcontrollers/rc" && m == "GET":
-				get := gets[0]
-				gets = gets[1:]
-				return get, nil
-			default:
-				t.Fatalf("unexpected request: %#v\n%#v", req.URL, req)
-				return nil, nil
-			}
-		}),
-	}
-	tf.ClientConfig = &client.Config{Version: latest.Version}
-	client, err := f.Client()
-	if err != nil {
-		t.Errorf("unexpected error: %v", err)
-		t.Fail()
-		return
-	}
-
-	if rc, err := updateWithRetries(
-		client.ReplicationControllers("default"), rc, func(c *api.ReplicationController) {
-			c.Spec.Selector["baz"] = "foobar"
-		}); err != nil {
-		t.Errorf("unexpected error: %v", err)
-	} else if sel, ok := rc.Spec.Selector["baz"]; !ok || sel != "foobar" || rc.ResourceVersion != "2" {
-		t.Errorf("Expected updated rc, got %+v", rc)
-	}
-	if len(updates) != 0 || len(gets) != 0 {
-		t.Errorf("Remaining updates %+v gets %+v", updates, gets)
-	}
-}
-
-func readOrDie(t *testing.T, req *http.Request, codec runtime.Codec) runtime.Object {
-	data, err := ioutil.ReadAll(req.Body)
-	if err != nil {
-		t.Errorf("Error reading: %v", err)
-		t.FailNow()
-	}
-	obj, err := codec.Decode(data)
-	if err != nil {
-		t.Errorf("error decoding: %v", err)
-		t.FailNow()
-	}
-	return obj
-}

pkg/kubectl/rolling_updater.go

@@ -17,13 +17,18 @@ limitations under the License.
 package kubectl
 
 import (
+	goerrors "errors"
 	"fmt"
 	"io"
 	"strconv"
+	"strings"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/fields"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/wait"
 )
 
@@ -71,6 +76,50 @@ const (
 	RenameRollingUpdateCleanupPolicy RollingUpdaterCleanupPolicy = "Rename"
 )
 
+func LoadExistingNextReplicationController(c *client.Client, namespace, newName string) (*api.ReplicationController, error) {
+	if len(newName) == 0 {
+		return nil, nil
+	}
+	newRc, err := c.ReplicationControllers(namespace).Get(newName)
+	if err != nil && errors.IsNotFound(err) {
+		return nil, nil
+	}
+	return newRc, err
+}
+
+func CreateNewControllerFromCurrentController(c *client.Client, namespace, oldName, newName, image, deploymentKey string) (*api.ReplicationController, error) {
+	// load the old RC into the "new" RC
+	newRc, err := c.ReplicationControllers(namespace).Get(oldName)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(newRc.Spec.Template.Spec.Containers) > 1 {
+		// TODO: support multi-container image update.
+		return nil, goerrors.New("Image update is not supported for multi-container pods")
+	}
+	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[0].Image = image
+
+	newHash, err := api.HashObject(newRc, c.Codec)
+	if err != nil {
+		return nil, err
+	}
+
+	if len(newName) == 0 {
+		newName = fmt.Sprintf("%s-%s", newRc.Name, newHash)
+	}
+	newRc.Name = newName
+
+	newRc.Spec.Selector[deploymentKey] = newHash
+	newRc.Spec.Template.Labels[deploymentKey] = newHash
+	// Clear resource version after hashing so that identical updates get different hashes.
+	newRc.ResourceVersion = ""
+	return newRc, nil
+}
+
 // NewRollingUpdater creates a RollingUpdater from a client
 func NewRollingUpdater(namespace string, c RollingUpdaterClient) *RollingUpdater {
 	return &RollingUpdater{
@@ -115,6 +164,138 @@ func SetNextControllerAnnotation(rc *api.ReplicationController, name string) {
 	rc.Annotations[nextControllerAnnotation] = name
 }
 
+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)
+	}
+}
+
+const MaxRetries = 3
+
+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.Fprint(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
+}
+
+type updateFunc func(controller *api.ReplicationController)
+
+// updateWithRetries updates applies the given rc as an update.
+func updateWithRetries(rcClient client.ReplicationControllerInterface, rc *api.ReplicationController, applyUpdate updateFunc) (*api.ReplicationController, error) {
+	// Each update could take ~100ms, so give it 0.5 second
+	var err error
+	oldRc := rc
+	err = wait.Poll(10*time.Millisecond, 500*time.Millisecond, func() (bool, error) {
+		// Apply the update, then attempt to push it to the apiserver.
+		applyUpdate(rc)
+		if rc, err = rcClient.Update(rc); err == nil {
+			// rc contains the latest controller post update
+			return true, nil
+		}
+		// Update the controller with the latest resource version, if the update failed we
+		// can't trust rc so use oldRc.Name.
+		if rc, err = rcClient.Get(oldRc.Name); err != nil {
+			// The Get failed: Value in rc cannot be trusted.
+			rc = oldRc
+		}
+		// The Get passed: rc contains the latest controller, expect a poll for the update.
+		return false, nil
+	})
+	// If the error is non-nil the returned controller cannot be trusted, if it is nil, the returned
+	// controller contains the applied update.
+	return rc, err
+}
+
+func FindSourceController(r RollingUpdaterClient, namespace, name string) (*api.ReplicationController, error) {
+	list, err := r.ListReplicationControllers(namespace, labels.Everything())
+	if err != nil {
+		return nil, err
+	}
+	for ix := range list.Items {
+		rc := &list.Items[ix]
+		if rc.Annotations != nil && strings.HasPrefix(rc.Annotations[sourceIdAnnotation], name) {
+			return rc, nil
+		}
+	}
+	return nil, fmt.Errorf("couldn't find a replication controller with source id == %s/%s", namespace, name)
+}
+
 // Update all pods for a ReplicationController (oldRc) by creating a new
 // controller (newRc) with 0 replicas, and synchronously resizing oldRc,newRc
 // by 1 until oldRc has 0 replicas and newRc has the original # of desired
@@ -286,19 +467,28 @@ func (r *RollingUpdater) updateAndWait(rc *api.ReplicationController, interval,
 }
 
 func (r *RollingUpdater) rename(rc *api.ReplicationController, newName string) error {
+	return Rename(r.c, rc, newName)
+}
+
+func Rename(c RollingUpdaterClient, rc *api.ReplicationController, newName string) error {
 	oldName := rc.Name
 	rc.Name = newName
 	rc.ResourceVersion = ""
 
-	_, err := r.c.CreateReplicationController(rc.Namespace, rc)
+	_, err := c.CreateReplicationController(rc.Namespace, rc)
 	if err != nil {
 		return err
 	}
-	return r.c.DeleteReplicationController(rc.Namespace, oldName)
+	err = c.DeleteReplicationController(rc.Namespace, oldName)
+	if err != nil && !errors.IsNotFound(err) {
+		return err
+	}
+	return nil
 }
 
 // RollingUpdaterClient abstracts access to ReplicationControllers.
 type RollingUpdaterClient interface {
+	ListReplicationControllers(namespace string, selector labels.Selector) (*api.ReplicationControllerList, error)
 	GetReplicationController(namespace, name string) (*api.ReplicationController, error)
 	UpdateReplicationController(namespace string, rc *api.ReplicationController) (*api.ReplicationController, error)
 	CreateReplicationController(namespace string, rc *api.ReplicationController) (*api.ReplicationController, error)
@@ -315,6 +505,10 @@ type realRollingUpdaterClient struct {
 	client client.Interface
 }
 
+func (c *realRollingUpdaterClient) ListReplicationControllers(namespace string, selector labels.Selector) (*api.ReplicationControllerList, error) {
+	return c.client.ReplicationControllers(namespace).List(selector)
+}
+
 func (c *realRollingUpdaterClient) GetReplicationController(namespace, name string) (*api.ReplicationController, error) {
 	return c.client.ReplicationControllers(namespace).Get(name)
 }