Kubernetes Role Based Access Control Concepts

Internal

• Kubernetes Security Concepts

Overview

In Kubernetes, granting a role to an application-specific service account is a best practice to ensure that the application is operated in a specified scope.

TODO:

• https://kubernetes.io/docs/reference/access-authn-authz/rbac/#service-account-permissions
• https://docs.bitnami.com/kubernetes/how-to/configure-rbac-in-your-kubernetes-cluster/

Cluster Role

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: edit
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
    rbac.authorization.k8s.io/aggregate-to-admin: "true"
  resourceVersion: "316"
aggregationRule:
  clusterRoleSelectors:
  - matchLabels:
      rbac.authorization.k8s.io/aggregate-to-edit: "true"
rules:
- apiGroups:
  - ""
  resources:
  - pods/attach
  - pods/exec
  - pods/portforward
  - pods/proxy
  - secrets
  - services/proxy
  verbs:
  - get
  - list
  - watch

Cluster Role Binding

A ClusterRoleBinding can be bound to only one role.

apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: cluster-admin
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: Group
  name: system:masters

Role

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: some-role
  namespace: some-namespace
rules:
- apiGroups:
  - ""
  resources:
  - pods
  verbs:
  - get
  - list
- apiGroups:
  - ""
  resourceNames:
  - some-specific-resourcename
  resources:
  - configmaps
  verbs:
  - get
  - update
  - patch

Role Binding

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  annotations:
  name: some-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: some-role
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: ServiceAccount
  name: system:serviceaccount:blue:blue-sa
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: some-user

RBAC Operations

• Assigning a Cluster Role to a Service Account