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我正在尝试编写一个 Go 程序来从集群中获取 pod 日志。我正在使用 AKS kubernetes 集群。如何访问脚本中的 kubeconfig 文件？以下是我的代码：

package main

import (
    "context"
    "flag"
    "fmt"
    "time"
    "os"
    "path/filepath"

    "k8s.io/apimachinery/pkg/api/errors"
    metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
    "k8s.io/client-go/kubernetes"
    //"k8s.io/client-go/rest"
    "k8s.io/client-go/tools/clientcmd"
    //
    // 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() {
    /*// creates the in-cluster config
    config, err := rest.InClusterConfig()
    if err != nil {
        panic(err.Error())
    }*/
    
    fmt.Printf("Creating cluster config")
    
    kubePtr := flag.Bool("use-kubeconfig", false, "use kubeconfig on local system")
    flag.Parse()
    
    fmt.Printf("Updating the existing config")

    var kubeconfig string

    if *kubePtr == true {
        kubeconfig = filepath.Join(os.Getenv("HOME"), ".kube", "config")
    } else {
        kubeconfig = ""
    }
    
    fmt.Printf("Building config from flags")

    config, err := clientcmd.BuildConfigFromKubeconfigGetter("", kubeconfig)
    
    fmt.Printf("creating the clientset")
    
    
    // creates the clientset
    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(), "example-xxxxx", metav1.GetOptions{})
        if errors.IsNotFound(err) {
            fmt.Printf("Pod example-xxxxx 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 example-xxxxx pod in default namespace\n")
        }

        time.Sleep(10 * time.Second)
    }
}

我在第 51 行遇到错误。以下是我的错误：

error creating inClusterConfig, falling back to default config: unable to load in-cluster configuration, KUBERNETES_SERVICE_HOST and KUBERNETES_SERVICE_PORT must be defined

我在哪里可以找到KUBERNETES_SERVICE_HOST以及KUBERNETES_SERVICE_PORT如何通过它？我找不到任何例子。

4

2 回答 2

1

From the example here the code should be like below. Notice the usage of BuildConfigFromFlags function to load the kubeconfig file.

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)
    }
    clientset, err := kubernetes.NewForConfig(config)
    if err != nil {
        panic(err)
    }
    ...

Make sure that there is a valid kubeconfig file at ~/.kube/config location. On AKS you can run below command to get the kubeconfig file which puts the file at ~/.kube/config

az aks get-credentials --resource-group myResourceGroup --name myAKSCluster
于 2020-08-28T08:47:08.867 回答
1

我注意到的第一件事是你没有提到你是如何开始你的程序的。

查看我看到的代码，您正在创建一个kubePtr默认为false. 当 flag 设置为true它时，它将 kubeconfig 变量设置为 kubeconfig 路径，但是因为它是 false（默认情况下）它将它设置为 ""，这就是它找不到配置的原因。

将此标志设置为 true 后，您会看到以下错误：

不能在 clientcmd.BuildConfigFromKubeconfigGetter 的参数中使用 kubeconfig（类型字符串）作为类型 clientcmd.KubeconfigGetter

这意味着你有类型不匹配。让我们看一下BuildConfigFromKubeconfigGetter() 函数参数类型：

func BuildConfigFromKubeconfigGetter(masterUrl string, kubeconfigGetter KubeconfigGetter) (*restclient.Config, error)

请注意，您正在传递一个字符串作为预期类型为KubeconfigGetter的参数。

最好使用不同的函数，如clientcmd.BuildConfigFromFlags()，作为参数期望kubeconfig 文件的路径（字符串）。

在 github 上的官方 client-go 库存储库中，您可以找到几个可以帮助您开始使用 clien-go 库的示例。

例如，看一下这个官方示例，并注意客户端是如何配置的。

于 2020-08-28T09:04:16.447 回答