Kubernetes API: cannot list resource "pods" in API group ""

Question

I'm trying to make a pod that will serve as the controller for other pods, basically creating and stopping them as needed. I initially created a ServiceAccount, a Role, a RoleBinding, and a simple Alpine container that I can use for testing with curl, all within a new Namespace. Here's my YAML file for all of this:

apiVersion: v1
kind: Namespace
metadata:
    name: nfv
    labels:
        name: nfv
---
apiVersion: v1
kind: ServiceAccount
metadata:
    name: nfv-svc
    namespace: nfv
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
    name: nfv-role
    namespace: nfv
rules:
    - apiGroups:
        - ''
      resources:
        - 'pods'
      verbs:
        - 'create'
        - 'delete'
        - 'get'
        - 'list'
        - 'patch'
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
    name: nfv-rolebind
subjects:
    - kind: ServiceAccount
      name: nfv-svc
      namespace: nfv
roleRef:
    kind: Role
    name: nfv-role
    apiGroup: rbac.authorization.k8s.io
---
apiVersion: v1
kind: Pod
metadata:
    name: sdn-test
    namespace: nfv
spec:
    serviceAccountName: nfv-svc
    containers:
        - image: alpine:3.9
          name: sdn-test-container
          command:
              - sleep
              - "10000"

Then I attach to the alpine test container and do the following:

apk add --update curl
CA_CERT=/run/secrets/kubernetes.io/serviceaccount/ca.crt
NAMESPACE=$(cat /var/run/secrets/kubernetes.io/serviceaccount/namespace)
TOKEN=$(cat /run/secrets/kubernetes.io/serviceaccount/token)
curl -H "Authorization: Bearer $TOKEN" --cacert $CA_CERT https://kubernetes.default/api/v1/namespaces/$NAMESPACE/pods

Then I get the following output:

{
  "kind": "Status",
  "apiVersion": "v1",
  "metadata": {
    
  },
  "status": "Failure",
  "message": "pods is forbidden: User \"system:serviceaccount:nfv:nfv-svc\" cannot list resource \"pods\" in API group \"\" in the namespace \"nfv\"",
  "reason": "Forbidden",
  "details": {
    "kind": "pods"
  },
  "code": 403
}

The Role should have sufficient permissions to list the pods in my namespace, so why is it not working? What am I missing? I'm using Kubernetes v1.18.2 on Ubuntu 16.04.

Answer 1

There needs to be a namespace namespace: nfv in the RoleBinding because it's a namespace scoped resource.

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
    name: nfv-rolebind
    namespace: nfv
subjects:
    - kind: ServiceAccount
      name: nfv-svc
      namespace: nfv
roleRef:
    kind: Role
    name: nfv-role
    apiGroup: rbac.authorization.k8s.io

To verify the permission you can use below command

kubectl auth can-i list pods --as=system:serviceaccount:nfv:nfv-svc -n nfv
yes