RBAC in Kubernetes

RBAC stands for Role Based Access Control

Under core api groups we have all objects: pods, deployments, Services, ReplicaSets, Statefulsets, jobs

Role: A role can be used to grant access to resources in a namespace.

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
  name: developer
  namespace: dev
- apiGroups: ["","Extensions", "apps"]  # "" indicates the core API group
  resources: ["*"]
  verbs: ["get", "list", "create", "delete", "watch"]
- apiGroups: ["batch"]
  - job
  - cronjobs
  verbs: ["*"]

RoleBinding: A RoleBinding binds subjects[users, groups] with the roles.

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
  name: dev-user-rolebinding
  namespace: dev
  kind: user
  name: dev
  apiGroup: rbac.authorization.k8s.io/v1
  kind: role
  name: developer
  apiGroup: rbac.authorization.k8s.io/v1

imperative command to create Roles and RoleBindings

kubectl create role developer --namespace=default --verb=list,create,delete --resource=pods
kubectl create rolebinding dev-user-rolebinding --namespace=default --role=developer --user=dev-user

kubectl auth can-i list nodes --as dev # to check access

clusterrole & clusterrolebinding :

# create cluster role
kubectl create clusterrole abi-clustaer-role \ 
  --namespace=dev --verb=list --resource=persistentvolumes

# create cluster rolebinding with a user
kubectl create rolebinding abi-cluster-rolebinding \
  --namespace= dev --clusterrole=abi-cluster-role --user=dev-user

# create cluster rolebinding with a service account
kubectl create rolebinding abi-cluster-rolebinding \
--namespace= dev --clusterrole=abi-cluster-role --serviceaccount-abi-serv-acnt