kubernetes - golang lib - missing permissions for test user

I use a watcherList, which is supported by the official golang kubernetes lib, to get notifications about created, updated and removed services inside a kubernetes namespace. Here the snippet.

func (kc *KubernetesCollector) streamEvents(ctx context.Context) {
    kc.debugChannel <- fmt.Sprintf("Start streaming events from kubernetes API")

    watchList := cache.NewListWatchFromClient(kc.k8sClient.RESTClient(), "services", kc.k8sNamespace, fields.Everything())

    notificationCallbackToAddService := func(svc interface{}) {
        service := svc.(*v1.Service)
        kc.serviceNotificationChannel <- &serviceNotification{service, "add"}
    }

    notificationCallbackToDeleteService := func(svc interface{}) {
        service := svc.(*v1.Service)
        kc.serviceNotificationChannel <- &serviceNotification{service, "remove"}
    }

    callbacks := cache.ResourceEventHandlerFuncs{
        AddFunc:    notificationCallbackToAddService,
        DeleteFunc: notificationCallbackToDeleteService,
    }

    _, controller := cache.NewInformer(watchList, &v1.Service{}, time.Second*0, callbacks)
    go controller.Run(ctx.Done())
}

In my test I declare the kc.k8sClient over the public api address, which is defined in k8sAPI variable. Additionally I set the bearer token to authenticate against the cluster and skip to verify the insecure ssl certificate.

func TestK8sWatchList(t *testing.T) {
    require := require.New(t)
    ...
    k8sConfig, err := clientcmd.BuildConfigFromFlags(k8sAPI, "")
    require.NoError(err)

    k8sConfig.BearerToken = "<bearerToken>"
    k8sConfig.Transport = &http.Transport{
        TLSClientConfig: &tls.Config{
            InsecureSkipVerify: true,
        },
    }
    k8sClient, err := kubernetes.NewForConfig(k8sConfig)

    k8sCollector := NewK8sCollector(k8sClient, k8sNamespace)

    ...
}

When I execute the test, I receive the following error messages:

go test -v -timeout 500s <replaced>/t1k/pkg/collector -run TestK8sWatchList
=== RUN   TestK8sWatchList
11.02.2020 16:55:55 DEBUG: Start streaming events from kubernetes API
E0211 16:55:51.706530  121803 reflector.go:153] pkg/mod/k8s.io/client-go@v0.0.0-20200106225816-7985654fe8ee/tools/cache/reflector.go:105: Failed to list *v1.Service: forbidden: User "system:serviceaccount:t1k:t1k-test-serviceaccount" cannot get path "/namespaces/t1k/services"
E0211 16:55:52.707520  121803 reflector.go:153] pkg/mod/k8s.io/client-go@v0.0.0-20200106225816-7985654fe8ee/tools/cache/reflector.go:105: Failed to list *v1.Service: forbidden: User "system:serviceaccount:t1k:t1k-test-serviceaccount" cannot get path "/namespaces/t1k/services"
E0211 16:55:53.705539  121803 reflector.go:153] pkg/mod/k8s.io/client-go@v0.0.0-20200106225816-7985654fe8ee/tools/cache/reflector.go:105: Failed to list *v1.Service: forbidden: User "system:serviceaccount:t1k:t1k-test-serviceaccount" cannot get path "/namespaces/t1k/services"

I don't understand why I get the error message, because the service account "t1k-test-serviceaccount" has in my opinion all required permissions. Now the defined service account, role and rolebinding for the test user.

apiVersion: v1
kind: ServiceAccount
metadata:
  namespace: t1k
  name: t1k-test-serviceaccount
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: t1k
  name: t1k-test-role
rules:
- apiGroups: [""]   # "" indicates the core API group
  resources: ["*"]
  verbs: ["*"]
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  namespace: t1k
  name: t1k-test-rolebinding
subjects:
- name: t1k-test-serviceaccount
  kind: ServiceAccount
  apiGroup: ""
roleRef:
  name: t1k-test-role
  kind: Role
  apiGroup: rbac.authorization.k8s.io

Additional informations:

• kubeadm version 1.15.9
• kubectl version 1.17.2
• golib versions
  • k8s.io/api v0.17.2
  • k8s.io/apimachinery v0.17.2
  • k8s.io/client-go v0.0.0-20200106225816-7985654fe8ee
  • k8s.io/utils v0.0.0-20200117235808-5f6fbceb4c31 // indirect