First part of improved rolling update, allow dynamic next replication controller generation.

contrib/completions/bash/kubectl

@@ -405,11 +405,20 @@ _kubectl_rolling-update()
     flags_with_completion=()
     flags_completion=()
 
+    flags+=("--deployment-label-key=")
+    flags+=("--dry-run")
     flags+=("--filename=")
     two_word_flags+=("-f")
     flags+=("--help")
     flags+=("-h")
+    flags+=("--image=")
+    flags+=("--no-headers")
+    flags+=("--output=")
+    two_word_flags+=("-o")
+    flags+=("--output-version=")
     flags+=("--poll-interval=")
+    flags+=("--template=")
+    two_word_flags+=("-t")
     flags+=("--timeout=")
     flags+=("--update-period=")
 

docs/kubectl.md

@@ -66,4 +66,4 @@ kubectl
 * [kubectl update](kubectl_update.md)	 - Update a resource by filename or stdin.
 * [kubectl version](kubectl_version.md)	 - Print the client and server version information.
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.406236586 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.641615471 +0000 UTC

docs/kubectl_api-versions.md

@@ -50,4 +50,4 @@ kubectl api-versions
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405815046 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.640579424 +0000 UTC

docs/kubectl_cluster-info.md

@@ -50,4 +50,4 @@ kubectl cluster-info
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405639667 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.640382538 +0000 UTC

docs/kubectl_config.md

@@ -63,4 +63,4 @@ kubectl config SUBCOMMAND
 * [kubectl config use-context](kubectl_config_use-context.md)	 - Sets the current-context in a kubeconfig file
 * [kubectl config view](kubectl_config_view.md)	 - displays Merged kubeconfig settings or a specified kubeconfig file.
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405466384 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.640154327 +0000 UTC

docs/kubectl_config_set-cluster.md

@@ -65,4 +65,4 @@ $ kubectl config set-cluster e2e --insecure-skip-tls-verify=true
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.404357726 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.638291301 +0000 UTC

docs/kubectl_config_set-context.md

@@ -58,4 +58,4 @@ $ kubectl config set-context gce --user=cluster-admin
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.40472172 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.638842283 +0000 UTC

docs/kubectl_config_set-credentials.md

@@ -78,4 +78,4 @@ $ kubectl set-credentials cluster-admin --client-certificate=~/.kube/admin.crt -
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.40454463 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.638596132 +0000 UTC

docs/kubectl_config_set.md

@@ -52,4 +52,4 @@ kubectl config set PROPERTY_NAME PROPERTY_VALUE
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.404916515 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.639475859 +0000 UTC

docs/kubectl_config_unset.md

@@ -51,4 +51,4 @@ kubectl config unset PROPERTY_NAME
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405094144 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.639702273 +0000 UTC

docs/kubectl_config_use-context.md

@@ -50,4 +50,4 @@ kubectl config use-context CONTEXT_NAME
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405277784 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.639928664 +0000 UTC

docs/kubectl_config_view.md

@@ -73,4 +73,4 @@ $ kubectl config view -o template --template='{{range .users}}{{ if eq .name "e2
 ### SEE ALSO
 * [kubectl config](kubectl_config.md)	 - config modifies kubeconfig files
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.404151238 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.638011058 +0000 UTC

docs/kubectl_create.md

@@ -63,4 +63,4 @@ $ cat pod.json | kubectl create -f -
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.400230448 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.633893126 +0000 UTC

docs/kubectl_delete.md

@@ -81,4 +81,4 @@ $ kubectl delete pods --all
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.400618492 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.634491315 +0000 UTC

docs/kubectl_describe.md

@@ -63,4 +63,4 @@ $ kubectl describe pods/nginx
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 21:21:05.485819349 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.633584776 +0000 UTC

docs/kubectl_exec.md

@@ -64,4 +64,4 @@ $ kubectl exec -p 123456-7890 -c ruby-container -i -t -- bash -il
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.401622652 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.636226358 +0000 UTC

docs/kubectl_expose.md

@@ -82,4 +82,4 @@ $ kubectl expose streamer --port=4100 --protocol=udp --service-name=video-stream
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.403631642 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.637486796 +0000 UTC

docs/kubectl_get.md

@@ -85,4 +85,4 @@ $ kubectl get rc/web service/frontend pods/web-pod-13je7
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.399795546 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.633184922 +0000 UTC

docs/kubectl_label.md

@@ -81,4 +81,4 @@ $ kubectl label pods foo bar-
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.403876136 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.637727935 +0000 UTC

docs/kubectl_log.md

@@ -62,4 +62,4 @@ $ kubectl log -f 123456-7890 ruby-container
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.400998066 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.634970712 +0000 UTC

docs/kubectl_namespace.md

@@ -53,4 +53,4 @@ kubectl namespace [namespace]
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.400806182 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.634703492 +0000 UTC

docs/kubectl_port-forward.md

@@ -68,4 +68,4 @@ $ kubectl port-forward -p mypod 0:5000
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.40181203 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.636454335 +0000 UTC

docs/kubectl_proxy.md

@@ -65,4 +65,4 @@ $ kubectl proxy --api-prefix=k8s-api
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.402034031 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.636689051 +0000 UTC

docs/kubectl_resize.md

@@ -68,4 +68,4 @@ $ kubectl resize --current-replicas=2 --replicas=3 replicationcontrollers foo
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.401412855 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.635916597 +0000 UTC

docs/kubectl_rolling-update.md

@@ -23,14 +23,25 @@ $ kubectl rolling-update frontend-v1 -f frontend-v2.json
 
 // Update pods of frontend-v1 using JSON data passed into stdin.
 $ cat frontend-v2.json | kubectl rolling-update frontend-v1 -f -
+
+// Update the pods of frontend-v1 to frontend-v2 by just changing the image
+$ kubectl rolling-update frontend-v1 frontend-v2 --image=image:v2
+
 ```
 
 ### Options
 
 ```
+      --deployment-label-key="deployment": The key to use to differentiate between two different controllers, default 'deployment'.  Only relevant when --image is specified, ignored otherwise
+      --dry-run=false: If true, print out the changes that would be made, but don't actually make them.
   -f, --filename="": Filename or URL to file to use to create the new controller.
   -h, --help=false: help for rolling-update
+      --image="": Image to upgrade the controller to.  Can not be used with --filename/-f
+      --no-headers=false: When using the default output, don't print headers.
+  -o, --output="": Output format. One of: json|yaml|template|templatefile.
+      --output-version="": Output the formatted object with the given version (default api-version).
       --poll-interval="3s": Time delay between polling controller status after update. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
+  -t, --template="": Template string or path to template file to use when -o=template or -o=templatefile.  The template format is golang templates [http://golang.org/pkg/text/template/#pkg-overview]
       --timeout="5m0s": Max time to wait for a controller to update before giving up. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
       --update-period="1m0s": Time to wait between updating pods. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
 ```
@@ -68,4 +79,4 @@ $ cat frontend-v2.json | kubectl rolling-update frontend-v1 -f -
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.401210692 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-24 04:16:19.186748349 +0000 UTC

docs/kubectl_run-container.md

@@ -78,4 +78,4 @@ $ kubectl run-container nginx --image=nginx --overrides='{ "apiVersion": "v1beta
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.402296924 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.636970945 +0000 UTC

docs/kubectl_stop.md

@@ -72,4 +72,4 @@ $ kubectl stop -f path/to/resources
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.402507426 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.637194082 +0000 UTC

docs/kubectl_update.md

@@ -67,4 +67,4 @@ $ kubectl update pods my-pod --patch='{ "apiVersion": "v1beta1", "desiredState":
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.400435658 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.634205944 +0000 UTC

docs/kubectl_version.md

@@ -51,4 +51,4 @@ kubectl version
 ### SEE ALSO
 * [kubectl](kubectl.md)	 - kubectl controls the Kubernetes cluster manager
 
-###### Auto generated by spf13/cobra at 2015-04-23 00:47:55.405995955 +0000 UTC
+###### Auto generated by spf13/cobra at 2015-04-23 23:29:05.640847018 +0000 UTC

docs/man/man1/kubectl-rolling-update.1

@@ -22,6 +22,14 @@ existing controller and overwrite at least one (common) label in its replicaSele
 
 
 .SH OPTIONS
+.PP
+\fB\-\-deployment\-label\-key\fP="deployment"
+    The key to use to differentiate between two different controllers, default 'deployment'.  Only relevant when \-\-image is specified, ignored otherwise
+
+.PP
+\fB\-\-dry\-run\fP=false
+    If true, print out the changes that would be made, but don't actually make them.
+
 .PP
 \fB\-f\fP, \fB\-\-filename\fP=""
     Filename or URL to file to use to create the new controller.
@@ -30,10 +38,31 @@ existing controller and overwrite at least one (common) label in its replicaSele
 \fB\-h\fP, \fB\-\-help\fP=false
     help for rolling\-update
 
+.PP
+\fB\-\-image\fP=""
+    Image to upgrade the controller to.  Can not be used with \-\-filename/\-f
+
+.PP
+\fB\-\-no\-headers\fP=false
+    When using the default output, don't print headers.
+
+.PP
+\fB\-o\fP, \fB\-\-output\fP=""
+    Output format. One of: json|yaml|template|templatefile.
+
+.PP
+\fB\-\-output\-version\fP=""
+    Output the formatted object with the given version (default api\-version).
+
 .PP
 \fB\-\-poll\-interval\fP="3s"
     Time delay between polling controller status after update. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
 
+.PP
+\fB\-t\fP, \fB\-\-template\fP=""
+    Template string or path to template file to use when \-o=template or \-o=templatefile.  The template format is golang templates [
+\[la]http://golang.org/pkg/text/template/#pkg-overview\[ra]]
+
 .PP
 \fB\-\-timeout\fP="5m0s"
     Max time to wait for a controller to update before giving up. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".
@@ -156,6 +185,10 @@ $ kubectl rolling\-update frontend\-v1 \-f frontend\-v2.json
 // Update pods of frontend\-v1 using JSON data passed into stdin.
 $ cat frontend\-v2.json | kubectl rolling\-update frontend\-v1 \-f \-
 
+// Update the pods of frontend\-v1 to frontend\-v2 by just changing the image
+$ kubectl rolling\-update frontend\-v1 frontend\-v2 \-\-image=image:v2
+
+
 .fi
 .RE
 

pkg/kubectl/cmd/rollingupdate.go

@@ -17,14 +17,22 @@ limitations under the License.
 package cmd
 
 import (
+	"bytes"
+	"crypto/md5"
+	"errors"
 	"fmt"
 	"io"
 	"os"
+	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/fields"
 	"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/spf13/cobra"
 )
 
@@ -41,7 +49,11 @@ existing controller and overwrite at least one (common) label in its replicaSele
 $ kubectl rolling-update frontend-v1 -f frontend-v2.json
 
 // Update pods of frontend-v1 using JSON data passed into stdin.
-$ cat frontend-v2.json | kubectl rolling-update frontend-v1 -f -`
+$ cat frontend-v2.json | kubectl rolling-update frontend-v1 -f -
+
+// Update the pods of frontend-v1 to frontend-v2 by just changing the image
+$ kubectl rolling-update frontend-v1 frontend-v2 --image=image:v2
+`
 )
 
 func NewCmdRollingUpdate(f *cmdutil.Factory, out io.Writer) *cobra.Command {
@@ -61,33 +73,70 @@ func NewCmdRollingUpdate(f *cmdutil.Factory, out io.Writer) *cobra.Command {
 	cmd.Flags().String("poll-interval", pollInterval, `Time delay between polling controller status after update. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".`)
 	cmd.Flags().String("timeout", timeout, `Max time to wait for a controller to update before giving up. Valid time units are "ns", "us" (or "µs"), "ms", "s", "m", "h".`)
 	cmd.Flags().StringP("filename", "f", "", "Filename or URL to file to use to create the new controller.")
+	cmd.Flags().String("image", "", "Image to upgrade the controller to.  Can not be used with --filename/-f")
+	cmd.Flags().String("deployment-label-key", "deployment", "The key to use to differentiate between two different controllers, default 'deployment'.  Only relevant when --image is specified, ignored otherwise")
+	cmd.Flags().Bool("dry-run", false, "If true, print out the changes that would be made, but don't actually make them.")
+	cmdutil.AddPrinterFlags(cmd)
 	return cmd
 }
 
+func validateArguments(cmd *cobra.Command, args []string) (deploymentKey, filename, image, oldName string, err error) {
+	deploymentKey = cmdutil.GetFlagString(cmd, "deployment-label-key")
+	filename = cmdutil.GetFlagString(cmd, "filename")
+	image = cmdutil.GetFlagString(cmd, "image")
+
+	if len(deploymentKey) == 0 {
+		return "", "", "", "", cmdutil.UsageError(cmd, "--deployment-label-key can not be empty")
+	}
+	if len(filename) == 0 && len(image) == 0 {
+		return "", "", "", "", cmdutil.UsageError(cmd, "Must specify --filename or --image for new controller")
+	}
+	if len(filename) != 0 && len(image) != 0 {
+		return "", "", "", "", cmdutil.UsageError(cmd, "--filename and --image can not both be specified")
+	}
+	if len(image) > 0 && len(args) < 2 {
+		return "", "", "", "", cmdutil.UsageError(cmd, "You must specify a name for your new controller")
+	}
+	if len(args) < 1 {
+		return "", "", "", "", cmdutil.UsageError(cmd, "Must specify the controller to update")
+	}
+
+	return deploymentKey, filename, image, args[0], nil
+}
+
 func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, args []string) error {
 	if os.Args[1] == "rollingupdate" {
 		printDeprecationWarning("rolling-update", "rollingupdate")
 	}
-
+	deploymentKey, filename, image, oldName, err := validateArguments(cmd, args)
-	filename := cmdutil.GetFlagString(cmd, "filename")
+	if err != nil {
-	if len(filename) == 0 {
+		return err
-		return cmdutil.UsageError(cmd, "Must specify filename for new controller")
 	}
 	period := cmdutil.GetFlagDuration(cmd, "update-period")
 	interval := cmdutil.GetFlagDuration(cmd, "poll-interval")
 	timeout := cmdutil.GetFlagDuration(cmd, "timeout")
-	if len(args) != 1 {
+	dryrun := cmdutil.GetFlagBool(cmd, "dry-run")
-		return cmdutil.UsageError(cmd, "Must specify the controller to update")
-	}
-	oldName := args[0]
 
 	cmdNamespace, err := f.DefaultNamespace()
 	if err != nil {
 		return err
 	}
 
+	client, err := f.Client()
+	if err != nil {
+		return err
+	}
+
+	// fetch rc
+	oldRc, err := client.ReplicationControllers(cmdNamespace).Get(oldName)
+	if err != nil {
+		return err
+	}
+
 	mapper, typer := f.Object()
-	// TODO: use resource.Builder instead
+	var newRc *api.ReplicationController
+
+	if len(filename) != 0 {
 		obj, err := resource.NewBuilder(mapper, typer, f.ClientMapperForCommand()).
 			NamespaceParam(cmdNamespace).RequireNamespace().
 			FilenameParam(filename).
@@ -96,29 +145,53 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 		if err != nil {
 			return err
 		}
-	newRc, ok := obj.(*api.ReplicationController)
+		var ok bool
+		newRc, ok = obj.(*api.ReplicationController)
 		if !ok {
 			return cmdutil.UsageError(cmd, "%s does not specify a valid ReplicationController", filename)
 		}
+	}
+	if len(image) != 0 {
+		newName := args[1]
+		var err error
+		// 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 err != nil {
+			return err
+		}
+		newRc.Name = newName
+
+		newRc.Spec.Selector[deploymentKey] = newHash
+		newRc.Spec.Template.Labels[deploymentKey] = newHash
+		newRc.ResourceVersion = ""
+
+		if _, found := oldRc.Spec.Selector[deploymentKey]; !found {
+			if err := addDeploymentKeyToReplicationController(oldRc, client, deploymentKey, cmdNamespace, out); err != nil {
+				return err
+			}
+		}
+	}
 	newName := newRc.Name
 	if oldName == newName {
 		return cmdutil.UsageError(cmd, "%s cannot have the same name as the existing ReplicationController %s",
 			filename, oldName)
 	}
 
-	client, err := f.Client()
-	if err != nil {
-		return err
-	}
-
 	updater := kubectl.NewRollingUpdater(newRc.Namespace, kubectl.NewRollingUpdaterClient(client))
 
-	// fetch rc
-	oldRc, err := client.ReplicationControllers(newRc.Namespace).Get(oldName)
-	if err != nil {
-		return err
-	}
-
 	var hasLabel bool
 	for key, oldValue := range oldRc.Spec.Selector {
 		if newValue, ok := newRc.Spec.Selector[key]; ok && newValue != oldValue {
@@ -134,6 +207,18 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	if newRc.Spec.Replicas == 0 {
 		newRc.Spec.Replicas = oldRc.Spec.Replicas
 	}
+	if dryrun {
+		oldRcData := &bytes.Buffer{}
+		if err := f.PrintObject(cmd, oldRc, oldRcData); err != nil {
+			return err
+		}
+		newRcData := &bytes.Buffer{}
+		if err := f.PrintObject(cmd, 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
+	}
 	err = updater.Update(&kubectl.RollingUpdaterConfig{
 		Out:           out,
 		OldRc:         oldRc,
@@ -150,3 +235,68 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	fmt.Fprintf(out, "%s\n", newName)
 	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
+
+func addDeploymentKeyToReplicationController(oldRc *api.ReplicationController, client *client.Client, deploymentKey, namespace string, out io.Writer) error {
+	oldHash, err := hashObject(oldRc, client.Codec)
+	if err != nil {
+		return err
+	}
+	// Update all labels to include the new hash, 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 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 err
+		}
+	}
+	if oldRc.Spec.Selector == nil {
+		oldRc.Spec.Selector = map[string]string{}
+	}
+	if oldRc.Spec.Template.Labels == nil {
+		oldRc.Spec.Template.Labels = map[string]string{}
+	}
+	oldRc.Spec.Selector[deploymentKey] = oldHash
+	oldRc.Spec.Template.Labels[deploymentKey] = oldHash
+
+	if _, err := client.ReplicationControllers(namespace).Update(oldRc); err != nil {
+		return err
+	}
+	// Note there is still a race here, if a pod was created during the update phase.
+	// It's unlikely, but it could happen, and if it does, we'll create extra pods.
+	// TODO: Clean up orphaned pods here.
+
+	return nil
+}

pkg/kubectl/cmd/rollingupdate_test.go

@@ -0,0 +1,177 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package cmd
+
+import (
+	"bytes"
+	"net/http"
+	"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/util"
+)
+
+func TestValidateArgs(t *testing.T) {
+	f, _, _ := NewAPIFactory()
+
+	tests := []struct {
+		flags     map[string]string
+		args      []string
+		expectErr bool
+		testName  string
+	}{
+		{
+			expectErr: true,
+			testName:  "nothing",
+		},
+		{
+			flags:     map[string]string{},
+			args:      []string{"foo"},
+			expectErr: true,
+			testName:  "no file, no image",
+		},
+		{
+			flags: map[string]string{
+				"filename": "bar.yaml",
+			},
+			args:     []string{"foo"},
+			testName: "valid file example",
+		},
+		{
+			flags: map[string]string{
+				"image": "foo:v2",
+			},
+			args:      []string{"foo"},
+			expectErr: true,
+			testName:  "missing second image name",
+		},
+		{
+			flags: map[string]string{
+				"image": "foo:v2",
+			},
+			args:     []string{"foo", "foo-v2"},
+			testName: "valid image example",
+		},
+		{
+			flags: map[string]string{
+				"image":    "foo:v2",
+				"filename": "bar.yaml",
+			},
+			args:      []string{"foo", "foo-v2"},
+			expectErr: true,
+			testName:  "both filename and image example",
+		},
+	}
+	for _, test := range tests {
+		out := &bytes.Buffer{}
+		cmd := NewCmdRollingUpdate(f, out)
+
+		if test.flags != nil {
+			for key, val := range test.flags {
+				cmd.Flags().Set(key, val)
+			}
+		}
+		_, _, _, _, err := validateArguments(cmd, test.args)
+		if err != nil && !test.expectErr {
+			t.Errorf("unexpected error: %v (%s)", err, test.testName)
+		}
+		if err == nil && test.expectErr {
+			t.Error("unexpected non-error (%s)", test.testName)
+		}
+	}
+}
+
+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")
+				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")
+				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")
+				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")
+	}
+}