我有一个 golang 程序，我需要向K8S API server状态 (livez) api 添加一个新调用以获取健康状态。https://kubernetes.io/docs/reference/using-api/health-checks/该程序应该在 api 服务器的同一集群上运行并且需要获取/livez状态，我试图在 client-go lib 中找到这个 API，但没有找到实现它的方法......https://github.com/kubernetes/client-go有没有办法从运行在 API 服务器运行的同一集群上的 Go 程序中做到这一点？
1 回答
守着一只汪
TA贡献1872条经验 获得超3个赞
更新（最终答案）
附加
OP要求我修改我的答案以显示“微调”或“特定”服务帐户的配置，而不使用集群管理员..
据我所知，/healthz默认情况下，每个 pod 都具有读取权限。例如，以下内容CronJob在不使用 aServiceAccount的情况下也可以正常工作：
# cronjob
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: is-healthz-ok-no-svc
spec:
schedule: "*/5 * * * *" # at every fifth minute
jobTemplate:
spec:
template:
spec:
######### serviceAccountName: health-reader-sa
containers:
- name: is-healthz-ok-no-svc
image: oze4/is-healthz-ok:latest
restartPolicy: OnFailure
原来的
我继续为此写了一个概念证明。您可以在此处找到完整的 repo，但代码如下。
main.go
package main
import (
"os"
"errors"
"fmt"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/rest"
)
func main() {
client, err := newInClusterClient()
if err != nil {
panic(err.Error())
}
path := "/healthz"
content, err := client.Discovery().RESTClient().Get().AbsPath(path).DoRaw()
if err != nil {
fmt.Printf("ErrorBadRequst : %s\n", err.Error())
os.Exit(1)
}
contentStr := string(content)
if contentStr != "ok" {
fmt.Printf("ErrorNotOk : response != 'ok' : %s\n", contentStr)
os.Exit(1)
}
fmt.Printf("Success : ok!")
os.Exit(0)
}
func newInClusterClient() (*kubernetes.Clientset, error) {
config, err := rest.InClusterConfig()
if err != nil {
return &kubernetes.Clientset{}, errors.New("Failed loading client config")
}
clientset, err := kubernetes.NewForConfig(config)
if err != nil {
return &kubernetes.Clientset{}, errors.New("Failed getting clientset")
}
return clientset, nil
}
dockerfile
FROM golang:latest
RUN mkdir /app
ADD . /app
WORKDIR /app
RUN go build -o main .
CMD ["/app/main"]
部署.yaml
（作为 CronJob）
# cronjob
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: is-healthz-ok
spec:
schedule: "*/5 * * * *" # at every fifth minute
jobTemplate:
spec:
template:
spec:
serviceAccountName: is-healthz-ok
containers:
- name: is-healthz-ok
image: oze4/is-healthz-ok:latest
restartPolicy: OnFailure
---
# service account
apiVersion: v1
kind: ServiceAccount
metadata:
name: is-healthz-ok
namespace: default
---
# cluster role binding
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: is-healthz-ok
subjects:
- kind: ServiceAccount
name: is-healthz-ok
namespace: default
roleRef:
kind: ClusterRole
##########################################################################
# Instead of assigning cluster-admin you can create your own ClusterRole #
# I used cluster-admin because this is a homelab #
##########################################################################
name: cluster-admin
apiGroup: rbac.authorization.k8s.io
---
截屏
成功的 CronJob 运行
更新 1
OP 询问如何部署“in-cluster-client-config”，所以我提供了一个示例部署（我正在使用的）..
你可以在这里找到回购
示例部署（我使用的是 CronJob，但它可以是任何东西）：
cronjob.yaml
apiVersion: batch/v1beta1
kind: CronJob
metadata:
name: remove-terminating-namespaces-cronjob
spec:
schedule: "0 */1 * * *" # at minute 0 of each hour aka once per hour
#successfulJobsHistoryLimit: 0
#failedJobsHistoryLimit: 0
jobTemplate:
spec:
template:
spec:
serviceAccountName: svc-remove-terminating-namespaces
containers:
- name: remove-terminating-namespaces
image: oze4/service.remove-terminating-namespaces:latest
restartPolicy: OnFailure
rbac.yaml
apiVersion: v1
kind: ServiceAccount
metadata:
name: svc-remove-terminating-namespaces
namespace: default
---
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: crb-namespace-reader-writer
subjects:
- kind: ServiceAccount
name: svc-remove-terminating-namespaces
namespace: default
roleRef:
kind: ClusterRole
##########################################################################
# Instead of assigning cluster-admin you can create your own ClusterRole #
# I used cluster-admin because this is a homelab #
##########################################################################
name: cluster-admin
apiGroup: rbac.authorization.k8s.io
---
原始答案
听起来您正在寻找的是来自 client-go 的“in-cluster-client-config”。
重要的是要记住，当使用“in-cluster-client-config”时，Go 代码中的 API 调用使用“that”pod 的服务帐户。只是想确保您使用有权读取“/livez”的帐户进行测试。
我测试了以下代码，我能够获得“livez”状态..
package main
import (
"errors"
"flag"
"fmt"
"path/filepath"
"k8s.io/client-go/kubernetes"
"k8s.io/client-go/tools/clientcmd"
"k8s.io/client-go/rest"
"k8s.io/client-go/util/homedir"
)
func main() {
// I find it easiest to use "out-of-cluster" for tetsing
// client, err := newOutOfClusterClient()
client, err := newInClusterClient()
if err != nil {
panic(err.Error())
}
livez := "/livez"
content, _ := client.Discovery().RESTClient().Get().AbsPath(livez).DoRaw()
fmt.Println(string(content))
}
func newInClusterClient() (*kubernetes.Clientset, error) {
config, err := rest.InClusterConfig()
if err != nil {
return &kubernetes.Clientset{}, errors.New("Failed loading client config")
}
clientset, err := kubernetes.NewForConfig(config)
if err != nil {
return &kubernetes.Clientset{}, errors.New("Failed getting clientset")
}
return clientset, nil
}
// I find it easiest to use "out-of-cluster" for tetsing
func newOutOfClusterClient() (*kubernetes.Clientset, error) {
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()
// use the current context in kubeconfig
config, err := clientcmd.BuildConfigFromFlags("", *kubeconfig)
if err != nil {
return nil, err
}
// create the clientset
client, err := kubernetes.NewForConfig(config)
if err != nil {
return nil, err
}
return client, nil
}
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