How to give all Kubernetes service accounts access to a specific namespace?

I have a RBAC enabled Kubernetes cluster in GCP

There are one namespace for Tiller and multiple for Services

Right now, I can assign reader role for a specific service account given it's full name

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  name: tiller-reader
  namespace: tiller
rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs:
    - "get"
    - "watch"
    - "list"
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: tiller-reader-role-binding
  namespace: tiller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: tiller-reader
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: User
    name: system:serviceaccount:my-namespace-1:my-namespace-1-service-account

The Service namespaces and accounts are created dynamically. How do I automatically give all services accounts access to the Tiller namespace, for example: to get pods?

Solution

to grant a role to all service accounts you must use the Group system:serviceaccounts.

you can try the following config :

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  name: tiller-reader
  namespace: tiller
rules:
  - apiGroups: [""]
    resources: ["pods"]
    verbs:
    - "get"
    - "watch"
    - "list"
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: tiller-reader-role-binding
  namespace: tiller
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: tiller-reader
subjects:
  - apiGroup: rbac.authorization.k8s.io
    kind: Group
    name: system:serviceaccounts