使用client-go工具调用kubernetes API接口的教程详解(v1.17版本)

目录

• 说明
• 效果
• 实现

• 1、拉取工具源码
• 2、创建目录结构

• 查询代码实例
• 创建deployment资源
• 更新deployment类型服务
• 删除deployment类型服务

package main
import (
	"fmt"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
)
func main() {
	config, err := clientcmd.BuildConfigFromFlags("", "kube/config")
	if err != nil {
		panic(err)
	}
	client, _ := kubernetes.NewForConfig(config)
	pods ,err := client.CoreV1().Pods("ferry").List(metav1.ListOptions{})
	if err != nil {
		fmt.Println(err)
		return
	}
	for _,v := range  pods.Items {
		fmt.Printf(" 命名空间是：%v\n pod名字：%v\n IP：%v\n\n",v.Namespace,v.Name,v.Status.PodIP)
	}
}

package main
import (
	"context"
	"fmt"
	"k8s.io/apimachinery/pkg/api/errors"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"time"
)
func main() {
	config, err := clientcmd.BuildConfigFromFlags("", "kube/config")
	if err != nil {
		panic(err)
	}
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err.Error())
	}
	for {
		// get pods in all the namespaces by omitting namespace
		// Or specify namespace to get pods in particular namespace
		pods, err := clientset.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})
		if err != nil {
			panic(err.Error())
		}
		fmt.Printf("There are %d pods in the cluster\n", len(pods.Items))
		// Examples for error handling:
		// - Use helper functions e.g. errors.IsNotFound()
		// - And/or cast to StatusError and use its properties like e.g. ErrStatus.Message
		_, err = clientset.CoreV1().Pods("default").Get(context.TODO(), "nginx-74959fc858-cp48w", metav1.GetOptions{})
		if errors.IsNotFound(err) {
			fmt.Printf("Pod nginx-74959fc858-cp48w not found in default namespace\n")
		} else if statusError, isStatus := err.(*errors.StatusError); isStatus {
			fmt.Printf("Error getting pod %v\n", statusError.ErrStatus.Message)
		} else if err != nil {
			panic(err.Error())
		} else {
			fmt.Printf("Found nginx-74959fc858-cp48w pod in default namespace\n")
		}
	 time.Sleep(3 * time.Second)
	}
}

package main
import (
	"fmt"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
)
func main() {
	config, err := clientcmd.BuildConfigFromFlags("", "kube/config")
	if err != nil {
		panic(err)
	}
	client, _ := kubernetes.NewForConfig(config)
	deploymentList, err := client.AppsV1().Deployments("default").List(metav1.ListOptions{})
	if err != nil {
		fmt.Println(err)
		return
	}
	for _,v := range deploymentList.Items {
		fmt.Printf(" 命名空间是：%v\n deployment服务名字：%v\n 副本个数：%v\n\n",v.Namespace,v.Name,v.Status.Replicas)
	}
}

package main
import (
	"context"
	"flag"
	"fmt"
	"path/filepath"
	appsv1 "k8s.io/api/apps/v1"
	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	//
	// Uncomment to load all auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth"
	//
	// Or uncomment to load specific auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth/azure"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/openstack"
)
func main() {
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" {
		kubeconfig = flag.String("kubeconfig", filepath.Join("config"), "(optional) absolute path to the kubeconfig file")
	} else {
		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
	}
	flag.Parse()
	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err)
	}
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}
	deploymentsClient := clientset.AppsV1().Deployments(apiv1.NamespaceDefault)
	deployment := &appsv1.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name: "nginx-deployment",
		},
		Spec: appsv1.DeploymentSpec{
			Replicas: int32Ptr(2),
			Selector: &metav1.LabelSelector{
				MatchLabels: map[string]string{
					"app": "nginx",
				},
			},
			Template: apiv1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: map[string]string{
						"app": "nginx",
					},
				},
				Spec: apiv1.PodSpec{
					Containers: []apiv1.Container{
						{
							Name:  "web",
							Image: "nginx:1.12",
							Ports: []apiv1.ContainerPort{
								{
									Name:          "http",
									Protocol:      apiv1.ProtocolTCP,
									ContainerPort: 80,
								},
							},
						},
					},
				},
			},
		},
	}
	// Create Deployment
	fmt.Println("Creating deployment nginx...")
	result, err := deploymentsClient.Create(context.TODO(), deployment, metav1.CreateOptions{})
	if err != nil {
		panic(err)
	}
	fmt.Printf("Created deployment %q.\n", result.GetObjectMeta().GetName())
}

package main
import (
	"context"
	"flag"
	"fmt"
	"path/filepath"
	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	"k8s.io/client-go/util/retry"
	//
	// Uncomment to load all auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth"
	//
	// Or uncomment to load specific auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth/azure"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/openstack"
)
func main() {
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" {
		kubeconfig = flag.String("kubeconfig", filepath.Join("config"), "(optional) absolute path to the kubeconfig file")
	} else {
		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
	}
	flag.Parse()
	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err)
	}
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}
	deploymentsClient := clientset.AppsV1().Deployments(apiv1.NamespaceDefault)
	retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
		// Retrieve the latest version of Deployment before attempting update
		// RetryOnConflict uses exponential backoff to avoid exhausting the apiserver
		result, getErr := deploymentsClient.Get(context.TODO(), "nginx-deployment", metav1.GetOptions{})
		if getErr != nil {
			panic(fmt.Errorf("Failed to get latest version of Deployment: %v", getErr))
		}
		result.Spec.Replicas = int32Ptr(1)                           // reduce replica count
		result.Spec.Template.Spec.Containers[0].Image = "nginx:1.13" // change nginx version
		_, updateErr := deploymentsClient.Update(context.TODO(), result, metav1.UpdateOptions{})
		return updateErr
	})
	if retryErr != nil {
		panic(fmt.Errorf("Update failed: %v", retryErr))
	}
	fmt.Println("Updated deployment nginx")
}
func int32Ptr(i int32) *int32 { return &i }

package main
import (
	"bufio"
	"context"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	apiv1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	//
	// Uncomment to load all auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth"
	//
	// Or uncomment to load specific auth plugins
	// _ "k8s.io/client-go/plugin/pkg/client/auth/azure"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/gcp"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/oidc"
	// _ "k8s.io/client-go/plugin/pkg/client/auth/openstack"
)
func main() {
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" {
		kubeconfig = flag.String("kubeconfig", filepath.Join( "config"), "(optional) absolute path to the kubeconfig file")
	} else {
		kubeconfig = flag.String("kubeconfig", "", "absolute path to the kubeconfig file")
	}
	flag.Parse()
	config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
	if err != nil {
		panic(err)
	}
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil {
		panic(err)
	}
	deploymentsClient := clientset.AppsV1().Deployments(apiv1.NamespaceDefault)
     prompt()
	fmt.Println("Deleting deployment nginx...")
	deletePolicy := metav1.DeletePropagationForeground
	if err := deploymentsClient.Delete(context.TODO(), "nginx-deployment", metav1.DeleteOptions{
		PropagationPolicy: &deletePolicy,
	}); err != nil {
		panic(err)
	}
	fmt.Println("Deleted deployment.")
}
func prompt() {
	fmt.Printf("-> Press Return key to continue, will delete!")
	scanner := bufio.NewScanner(os.Stdin)
	for scanner.Scan() {
		break
	}
	if err := scanner.Err(); err != nil {
		panic(err)
	}
	fmt.Println()
}
func int32Ptr(i int32) *int32 { return &i }