目錄
- 說明
- 效果
- 實現
- 1、拉取工具源碼
- 2、創建目錄結構
- 查詢代碼實例
- 創建deployment資源
- 更新deployment類型服務
- 刪除deployment類型服務
說明
可以調取k8s API 接口的工具有很多，這里我就介紹下client-go
gitlab上client-go項目地址: https://github.com/kubernetes/client-go
這個工具是由kubernetes官方指定維護的，大家可以放心使用
效果
運行完成后，可以直接獲取k8s集群信息等
實現
1、拉取工具源碼
注意事項：https://github.com/kubernetes/client-go/blob/master/INSTALL.md
總結：一定要拉取跟集群對應版本的工具源碼，比如我這里集群是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，所有依賴文件放在這了，可以直接使用client-go k8s1.17 api
2、創建目錄結構
集群的角色配置文件（默認在/root/.kube/config）
kube/config
查詢代碼實例
查詢pod信息
查看ferry命名空間下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(" 命名空間是：%v\n pod名字：%v\n IP：%v\n\n",v.Namespace,v.Name,v.Status.PodIP)
}
}
自動關聯依賴
go mod tidy
運行結果
$ go run kube-api.go
命名空間是：ferry
pod名字：ferry-backend-7949596679-h8lxb
IP：10.42.1.14
命名空間是：ferry
pod名字：ferry-mysql-8db8d49f7-6psbv
IP：10.42.1.11
查詢一個pod是否在一個命名空間下
https://github.com/kubernetes/client-go/blob/master/examples/in-cluster-client-configuration/main.go
每3秒檢查下nginx-74959fc858-cp48w是否在default命名空間下
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)
}
}
運行結果
$ 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
\\在集群種手動刪除了這個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
查詢deployment服務類型信息
查詢default命名空間下的deployment服務信息，服務名字、服務副本數
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(" 命名空間是：%v\n deployment服務名字：%v\n 副本個數：%v\n\n",v.Namespace,v.Name,v.Status.Replicas)
}
}
運行結果
$ go run kube-api.go
命名空間是：default
deployment服務名字：nginx
副本個數：2
創建deployment資源
https://github.com/kubernetes/client-go/blob/master/examples/create-update-delete-deployment/main.go
復制一個config文件到當前目錄下
創建一個deployment類型的nginx服務
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(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())
}
運行結果
$ go run deployment-create.go
Creating deployment nginx...
Created deployment "nginx-deployment".
更新deployment類型服務
https://github.com/kubernetes/client-go/blob/master/examples/create-update-delete-deployment/main.go
更改服務的副本數，由上一步創建的2修改成1，并修改鏡像由nginx1.12–>nginx1.13
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 }
運行結果
$ go run deployment-update.go
Updated deployment nginx
刪除deployment類型服務
刪除上面創建的nginx-deployment資源，刪除之前添加了確認語句
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(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 }
運行結果
$ go run deployment-delete.go
-> Press Return key to continue, will delete! 這里點擊回車后繼續刪除資源
Deleting deployment nginx...
Deleted deployment.
到此這篇關于使用client-go工具調kubernetes API接口(v1.17版本)的文章就介紹到這了,更多相關client-go調用kubernetes API內容請搜索腳本之家以前的文章或繼續瀏覽下面的相關文章希望大家以后多多支持腳本之家！
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