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
gitlab上client-go项目地址:https://github.com/kubernetes/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
注意事项:https://github.com/kubernetes/client-go/blob/master/INSTALL.md
要获得最新版本,使用go1.16+并使用go get命令获取。例如:
go get k8s.io/client-go@latest
要获得一个特定的版本,使用go1.11+并使用go get命令获取所需的版本。例如:
go get k8s.io/client-go@v0.20.4
本篇测试结果:拉取0.20.4的版本可以集成k8s集群是1.17版本
go get k8s.io/client-go@v0.20.4
我测试使用的是1.17版本的集群,所有client-go依赖文件放在这了,可以直接使用client-go k8s 1.17+ api
2、创建目录结构
目录位置:kube/config #集群的角色配置文件(默认在/root/.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"
"context"
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(context.TODO(), metav1.ListOptions{})
//client-go驱动0.17.0版本请把context.TODO(),去掉
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)
}
}
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
https://github.com/kubernetes/client-go/blob/master/examples/in-cluster-client-configuration/main.go 每3秒检查下nginx-74959fc858-cp48w 是否在default 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
deployment类型
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"
"context"
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(context.TODO(), 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)
}
}
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
https://github.com/kubernetes/client-go/blob/master/examples/create-update-delete-deployment/main.go
复制一个config文件到当前目录下
在默认命名空间在(default)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(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())
}
func int32Ptr(i int32) *int32 { return &i }
运行结果
$ go run deployment-create.go
Creating deployment nginx...
Created deployment "nginx-deployment".
创建指定命名空间下deployment服务 在指定ferry命名空间下创建一个deployment类型的nginx服务
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("ferry")
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())
}
func int32Ptr(i int32) *int32 { return &i }
更新deployment类型服务
https://github.com/kubernetes/client-go/blob/master/examples/create-update-delete-deployment/main.go 更改服务的副本数,由上一步创建的2修改成1,并修改镜像由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 }
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(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 }
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.
service类型(svc 服务发现)
查询svc服务信息
查询web命名空间下rancher中手动添加的DNS记录名字和IP地址
package main
import (
"context"
"fmt"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"strings"
"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().Services("web").List(context.TODO(), metav1.ListOptions{})
//client-go驱动0.17.0版本请把<< context.TODO(), >>去掉
if err != nil {
fmt.Println(err)
return
}
for _,v := range pods.Items {
hostname := v.Name
ip :=v.Annotations["field.cattle.io/ipAddresses"]
//测试查询到 v 变量中数组,字段与yaml文件对应
ss1 := strings.TrimLeft(ip,"[\"")
ss2 := strings.TrimRight(ss1,"]\"")
fmt.Printf(" svc名字:%v\n IP:%v\n\n",hostname,ss2)
}
}
运行结果
$ go run questtion-deployment.go
svc名字:emr01
IP:192.168.8.9
svc名字:emr02
IP:192.168.1.10
创建svc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"
//
// 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("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)
}
clientset, err := kubernetes.NewForConfig(config)
if err != nil {
panic(err)
}
deploymentsClient := clientset.CoreV1().Services("web")
service := &apiv1.Service{
ObjectMeta: metav1.ObjectMeta{
Name: "emr08",
Namespace: "web",
Annotations: map[string]string{
"field.cattle.io/ipAddresses": "[\"192.168.1.189\"]",
},
},
Spec: apiv1.ServiceSpec{
ClusterIP: "None",
Type: "ClusterIP",
Ports: []apiv1.ServicePort{ // 必填字段
{
Name: "emr03",
Protocol: apiv1.ProtocolTCP,
Port: 42,
},
},
},
}
// Create Deployment
fmt.Println("Creating service ...")
result, err := deploymentsClient.Create(context.TODO(), service, metav1.CreateOptions{})
if err != nil {
panic(err)
}
fmt.Printf("Created service %q.\n", result.GetObjectMeta().GetName())
}
func int32Ptr(i int32) *int32 { return &i }
运行结果
$ go run create-svc.go
Creating service ...
Created service "emr08".
修改svc服务信息
修改web命名空间svc emr02的IP地址
package main
import (
"context"
"flag"
"fmt"
"path/filepath"
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("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)
}
clientset, err := kubernetes.NewForConfig(config)
if err != nil {
panic(err)
}
var servicesClient = clientset.CoreV1().Services("web")
retryErr := retry.RetryOnConflict(retry.DefaultRetry, func() error {
result, getErr := servicesClient.Get(context.TODO(), "emr02", metav1.GetOptions{})
if getErr != nil {
panic(fmt.Errorf("Failed to get latest version of Services: %v", getErr))
}
result.Annotations["field.cattle.io/ipAddresses"] = "[\"192.168.1.189\"]"
//字段与yaml文件对应
_, updateErr := servicesClient.Update(context.TODO(), result, metav1.UpdateOptions{})
return updateErr
})
if retryErr != nil {
panic(fmt.Errorf("Update failed: %v", retryErr))
}
fmt.Println("Updated service ")
}
func int32Ptr(i int32) *int32 { return &i }
删除指定命名空间下的svc
删除ferry命名空间下的名字叫nginx-nodeport的svc,同样在删除前,做了一个待确认功能
vim service-delete.go
package main
import (
"bufio"
"context"
"flag"
"fmt"
"os"
"path/filepath"
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.CoreV1().Services("ferry")
prompt()
fmt.Println("Deleting services ...")
deletePolicy := metav1.DeletePropagationForeground
if err := deploymentsClient.Delete(context.TODO(), "nginx-nodeport",metav1.DeleteOptions{
PropagationPolicy: &deletePolicy,
}); err != nil {
panic(err)
}
fmt.Println("Deleted services.")
}
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 }
总结
以上提供的方法是根据github上修改的,官方提供了几个deployment例子,我新增了svc例子,其他服务类型类似语法,不懂的随时联系我~
|