Add support for --rollback.

pkg/kubectl/cmd/rollingupdate.go

@@ -82,6 +82,7 @@ func NewCmdRollingUpdate(f *cmdutil.Factory, out io.Writer) *cobra.Command {
 	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.")
+	cmd.Flags().Bool("rollback", false, "If true, this is a request to abort an existing rollout that is partially rolled out. It effectively reverses current and next and runs a rollout")
 	cmdutil.AddPrinterFlags(cmd)
 	return cmd
 }
@@ -171,10 +172,15 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 
 		if len(newName) > 0 {
 			newRc, err = client.ReplicationControllers(cmdNamespace).Get(newName)
-			if err != nil && !apierrors.IsNotFound(err) {
-				return err
+			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)
 			}
-			fmt.Fprint(out, "Found existing update in progress (%s), resuming.\n", newName)
 		}
 		if newRc == nil {
 			// load the old RC into the "new" RC
@@ -257,7 +263,7 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 	if keepOldName {
 		updateCleanupPolicy = kubectl.RenameRollingUpdateCleanupPolicy
 	}
-	err = updater.Update(&kubectl.RollingUpdaterConfig{
+	config := &kubectl.RollingUpdaterConfig{
 		Out:           out,
 		OldRc:         oldRc,
 		NewRc:         newRc,
@@ -265,7 +271,12 @@ func RunRollingUpdate(f *cmdutil.Factory, out io.Writer, cmd *cobra.Command, arg
 		Interval:      interval,
 		Timeout:       timeout,
 		CleanupPolicy: updateCleanupPolicy,
-	})
+	}
+	if cmdutil.GetFlagBool(cmd, "rollback") {
+		kubectl.AbortRollingUpdate(config)
+		client.ReplicationControllers(config.NewRc.Namespace).Update(config.NewRc)
+	}
+	err = updater.Update(config)
 	if err != nil {
 		return err
 	}

pkg/kubectl/rolling_updater.go

@@ -85,6 +85,24 @@ const (
 	nextControllerAnnotation  = kubectlAnnotationPrefix + "next-controller-id"
 )
 
+func AbortRollingUpdate(c *RollingUpdaterConfig) {
+	// Swap the controllers
+	tmp := c.OldRc
+	c.OldRc = c.NewRc
+	c.NewRc = tmp
+
+	if c.NewRc.Annotations == nil {
+		c.NewRc.Annotations = map[string]string{}
+	}
+	c.NewRc.Annotations[sourceIdAnnotation] = fmt.Sprintf("%s:%s", c.OldRc.Name, c.OldRc.UID)
+	desiredSize, found := c.OldRc.Annotations[desiredReplicasAnnotation]
+	if found {
+		fmt.Printf("Found desired replicas.")
+		c.NewRc.Annotations[desiredReplicasAnnotation] = desiredSize
+	}
+	c.CleanupPolicy = DeleteRollingUpdateCleanupPolicy
+}
+
 func GetNextControllerAnnotation(rc *api.ReplicationController) (string, bool) {
 	res, found := rc.Annotations[nextControllerAnnotation]
 	return res, found
@@ -237,7 +255,7 @@ func (r *RollingUpdater) getExistingNewRc(sourceId, name string) (rc *api.Replic
 		source := annotations[sourceIdAnnotation]
 		_, ok := annotations[desiredReplicasAnnotation]
 		if source != sourceId || !ok {
-			err = fmt.Errorf("Missing/unexpected annotations for controller %s: %s", name, annotations)
+			err = fmt.Errorf("Missing/unexpected annotations for controller %s, expected %s : %s", name, sourceId, annotations)
 		}
 		return
 	}