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

使⽤client-go⼯具调⽤kubernetesAPI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
说明
可以调取k8s API 接⼝的⼯具有很多，这⾥我就介绍下client-go
这个⼯具是由kubernetes官⽅指定维护的，⼤家可以放⼼使⽤
效果
运⾏完成后，可以直接获取k8s集群信息等
实现
1、拉取⼯具源码
总结：⼀定要拉取跟集群对应版本的⼯具源码，⽐如我这⾥集群是1.17版本，那我就拉取17版本
go get k8s.io/client-go@v0.17.0
我是1.17版本的集群，所有依赖⽂件放在这了，可以直接使⽤
2、创建⽬录结构
集群的⾓⾊配置⽂件（默认在/root/.kube/config）
kube/config
查询代码实例
查询pod信息
查看ferry命名空间下pod的信息，pod名字、pod的IP
vim kube-api.go
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",space,,v.Status.PodIP)
}
}
⾃动关联依赖
go mod tidy
运⾏结果
$ go run kube-api.go
命名空间是：ferry
pod名字：ferry-backend-7949596679-h8lxb
IP：10.42.1.14
命名空间是：ferry
pod名字：ferry-mysql-8db8d49f7-6psbv
IP：10.42.1.11
查询⼀个pod是否在⼀个命名空间下
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)
}
}
运⾏结果
$ go run kube-api.go
There are 22 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 22 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 22 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 23 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 22 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 22 pods in the cluster
Found nginx-74959fc858-cp48w pod in default namespace
There are 21 pods in the cluster
\\在集群种⼿动删除了这个pod
Pod nginx-74959fc858-cp48w not found in default namespace
There are 21 pods in the cluster
Pod nginx-74959fc858-cp48w not found in default namespace
查询deployment服务类型信息
查询default命名空间下的deployment服务信息，服务名字、服务副本数
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",space,,v.Status.Replicas) }
}
运⾏结果
$ go run kube-api.go
命名空间是：default
deployment服务名字：nginx
副本个数：2
创建deployment资源
复制⼀个config⽂件到当前⽬录下
创建⼀个deployment类型的nginx服务
vim deployment-create.go
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(spaceDefault)
deployment := &appsv1.Deployment{
ObjectMeta: metav1.ObjectMeta{
Name: "nginx-deployment",
},
Spec: appsv1.DeploymentSpec{
Replicas: int32Ptr(2),
Selector: &belSelector{
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())
}
运⾏结果
$ go run deployment-create.go
Creating deployment nginx...
Created deployment "nginx-deployment".
更新deployment类型服务
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(spaceDefault)
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 }
运⾏结果
$ go run deployment-update.go
Updated deployment nginx
删除deployment类型服务
删除上⾯创建的nginx-deployment资源，删除之前添加了确认语句
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(spaceDefault)
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 }
运⾏结果
$ go run deployment-delete.go
-> Press Return key to continue, will delete! 这⾥点击回车后继续删除资源
Deleting deployment nginx...
Deleted deployment.
到此这篇关于使⽤client-go⼯具调kubernetes API接⼝(v1.17版本)的⽂章就介绍到这了,更多相关client-go调⽤kubernetes API内容请搜索以前的⽂章或继续浏览下⾯的相关⽂章希望⼤家以后多多⽀持！。