kubernetes RBAC role verbs to exec to pod

Question

I my 1.9 cluster created this deployment role for the dev user. Deployment works as expected. Now I want to give exec and logs access to developer. What role I need to add for exec to the pod?

kind: Role
name: deployment-manager
  rules:
  - apiGroups: ["", "extensions", "apps"]
    resources: ["deployments", "replicasets", "pods"]
    verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]

Error message:

kubectl exec nginx -it -- sh  

Error from server (Forbidden): pods "nginx" is forbidden: User "dev" cannot create pods/exec in the namespace "dev"

Thanks SR

Answer 1

The RBAC docs say that

Most resources are represented by a string representation of their name, such as “pods”, just as it appears in the URL for the relevant API endpoint. However, some Kubernetes APIs involve a “subresource”, such as the logs for a pod. [...] To represent this in an RBAC role, use a slash to delimit the resource and subresource.

To allow a subject to read both pods and pod logs, and be able to exec into the pod, you would write:

kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  namespace: default
  name: pod-and-pod-logs-reader
rules:
- apiGroups: [""]
  resources: ["pods", "pods/log"]
  verbs: ["get", "list"]
- apiGroups: [""]
  resources: ["pods/exec"]
  verbs: ["create"]

Some client libraries may do an http GET to negotiate a websocket first, which would require the "get" verb. kubectl sends an http POST instead, that's why it requires the "create" verb in that case.