client-go连接kubernetes集群-create

Posted 2022-05-06 saynaihe

背景

client-go连接kubernetes集群-connect and list。都是查看获取list列表的。现在想用client-go创建应用该如何操作呢？

client-go连接kubernetes集群-create

创建一个namespace：

clientset.CoreV1().Namespaces().Create

package main

import (
	"context"
	"flag"
	"fmt"
	v1 "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"
	"path/filepath"
)

func main() 
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" 
		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "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.Error())
	

	// create the clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil 
		panic(err.Error())
	
	namespace := &v1.Namespace
		ObjectMeta: metav1.ObjectMeta
			Name: "zhangpeng",
		,
	
	result, err := clientset.CoreV1().Namespaces().Create(context.TODO(), namespace, metav1.CreateOptions)
	if err != nil 
		fmt.Println(err)
	 else 
		fmt.Printf("Create ns %s SuccessFul !", result.ObjectMeta.Name)
		list, _ := clientset.CoreV1().Namespaces().List(context.Background(), metav1.ListOptions)
		for _, item := range list.Items 
			fmt.Println(item.Name)

		
	
	//fmt.Println(clientset.ServerVersion())
	//list, _ := clientset.CoreV1().Namespaces().List(context.Background(), metav1.ListOptions)
	//for _, item := range list.Items 
	//	fmt.Println(item.Name)
	//
	//
	//fmt.Println("pod list in develop")
	//list1, _ := clientset.CoreV1().Pods("develop").List(context.Background(), metav1.ListOptions)
	//for _, item := range list1.Items 
	//	fmt.Println(item.Name)
	//
	//
	clientset.AppsV1()

嗯打印在一起了 也可以加个换行符？

创建一个deployment

deployment是属于appv1的apiversion.当然了Goland中corev1().后面可以试一下补全是没有deployment的选项的！



*v1.Deployment怎么处理呢？单独写一个deployment的yaml文件然后文件流读取？或者直接在go文件中定义deployment的配置？

生成yaml读取文件流的方式：

生成yaml文件

kubectl create deployment nginx --image=nginx -o yaml --dry-run=client >nginx.yaml

nginx.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: nginx
  name: nginx
spec:
  replicas: 1
  selector:
    matchLabels:
      app: nginx
  strategy: 
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: nginx
    spec:
      containers:
      - image: nginx
        name: nginx
        resources: 
status: 

将文件保存为src/yamls/nginx.yaml

main.go

package main

import (
	"context"
	"encoding/json"
	"flag"
	"fmt"
	"io/ioutil"
	v1 "k8s.io/api/apps/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/apimachinery/pkg/util/yaml"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	"k8s.io/client-go/util/homedir"
	"path/filepath"
)

func main() 
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" 
		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "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.Error())
	

	// create the clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil 
		panic(err.Error())
	
	b, err := ioutil.ReadFile("src/yamls/nginx.yaml")
	nginxDep := &v1.Deployment
	nginxJson, _ := yaml.ToJSON(b)
	if err = json.Unmarshal(nginxJson, nginxDep); err != nil 
		return
	
	if _, err = clientset.AppsV1().Deployments("zhangpeng").Create(context.Background(), nginxDep, metav1.CreateOptions); err != nil 
		fmt.Println(err)
		return
	

go run main.go

go run main.go再运行一遍

运行第二次就报错已经创建了，基本达到目标，其他的问题以后处理！

go文件中直接定义deployment的配置

package main

import (
	"context"
	"flag"
	"fmt"
	v1 "k8s.io/api/apps/v1"
	corev1 "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"
	"path/filepath"
)

func main() 
	var kubeconfig *string
	if home := homedir.HomeDir(); home != "" 
		kubeconfig = flag.String("kubeconfig", filepath.Join(home, ".kube", "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.Error())
	

	// create the clientset
	clientset, err := kubernetes.NewForConfig(config)
	if err != nil 
		panic(err.Error())
	
	namespace := "default"
	var replicas int32 = 1
	deployment := &v1.Deployment
		ObjectMeta: metav1.ObjectMeta
			Name: "nginx",
			Labels: map[string]string
				"app": "nginx",
				"env": "dev",
			,
		,
		Spec: v1.DeploymentSpec
			Replicas: &replicas,
			Selector: &metav1.LabelSelector
				MatchLabels: map[string]string
					"app": "nginx",
					"env": "dev",
				,
			,
			Template: corev1.PodTemplateSpec
				ObjectMeta: metav1.ObjectMeta
					Name: "nginx",
					Labels: map[string]string
						"app": "nginx",
						"env": "dev",
					,
				,
				Spec: corev1.PodSpec
					Containers: []corev1.Container
						
							Name:  "nginx",
							Image: "nginx:1.16.1",
							Ports: []corev1.ContainerPort
								
									Name:          "http",
									Protocol:      corev1.ProtocolTCP,
									ContainerPort: 80,
								,
							,
						,
					,
				,
			,
		,
	
	deploymentList, err := clientset.AppsV1().Deployments(namespace).Create(context.TODO(), deployment, metav1.CreateOptions)
	fmt.Println(err, deploymentList)

参照：https://blog.csdn.net/xujiamin0022016/article/details/123434916
以上两种方式我还是喜欢单独写yaml的方式…

总结

1. create就写这两个有代表性的了namespace and deployment.deployment还是很有代表性的…
2. yaml的方式还是很方便，还是喜欢文件流的方式。
3. 先简单搞一下crud。增删改查。然后想一下怎么整合一下一步一步来吧