kubernetes Calling Kubernetes API Rolling update with repliasets using kubernetes go client

Example

package main

import (
    //    "k8s.io/kubernetes/pkg/api"
    // unver "k8s.io/kubernetes/pkg/api/unversioned"
    "k8s.io/kubernetes/pkg/apis/extensions"
    "k8s.io/kubernetes/pkg/client/restclient"
    client "k8s.io/kubernetes/pkg/client/unversioned"
    "k8s.io/kubernetes/pkg/util/intstr"
    "log"
    "os"
)

var logger *log.Logger

const (
    //DEPLOYMENT           string = "nginx-deployment"
    DEPLOYMENT           string = "nginx-test"
    RevisionHistoryLimit int32  = 5
    SERVER               string = "http://172.21.1.11:8080"
    RevisionAnnotation   string = "deployment.kubernetes.io/revision"
)

func init() {
    logger = log.New(os.Stdout, "", 0)
}

func rollingUpdate(c *client.Client, dp *extensions.Deployment) error {

    // New a DeploymentStrategy
    ds := new(extensions.DeploymentStrategy)
    ds.Type = extensions.RollingUpdateDeploymentStrategyType
    ds.RollingUpdate = new(extensions.RollingUpdateDeployment)
    ds.RollingUpdate.MaxUnavailable = intstr.FromInt(int(dp.Spec.Replicas))

    dp.Spec.Strategy = *ds

    // Image
    //dp.Spec.Template.Spec.Containers[0].Image = "nginx:1.9.7"
    dp.Spec.Template.Spec.Containers[0].Image = "nginx:1.9"

    // Update
    //_, err := c.Extensions().Deployments(api.NamespaceDefault).Update(dp)
    _, err := c.Extensions().Deployments("ops").Update(dp)
    if err != nil {
        logger.Printf("Update Deployment Error: err=%s\n", err)
        return err
    }
    return nil
}

func main() {
    config := &restclient.Config{
        Host: SERVER,
    }

    c, err := client.New(config)
    if err != nil {
        logger.Fatalf("Could not connect to k8s api: err=%s\n", err)
    }

    //dp, err := c.Extensions().Deployments(api.NamespaceDefault).Get(DEPLOYMENT)
    dp, err := c.Extensions().Deployments("ops").Get(DEPLOYMENT)
    if err != nil {
        logger.Fatalf("Could not list deployments: err=%s\n", err)
    }

    rollingUpdate(c, dp)

}