I know there are a lot of similar questions but none of them has a solution as far as I have browsed. Coming to the issue, I have created a service account (using command), role (using .yaml file), role binding (using .yaml files). The role grants access only to the pods. But when I login into the dashboard (Token method) using the SA that the role is attached to, I'm able to view all the resources without any restrictions. Here are the file and commands used by me.
Role.yaml:
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
namespace: assembly-prod
name: testreadrole
rules:
- apiGroups: [""]
resources: ["pods"]
verbs: ["get", "watch", "list"]
RoleBinding.yaml
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: testrolebinding
namespace: assembly-prod
subjects:
- kind: ServiceAccount
name: testsa
apiGroup: ""
roleRef:
kind: Role
name: testreadrole
apiGroup: rbac.authorization.k8s.io
Command used to create service account:
kubectl create serviceaccount <saname> --namespace <namespacename>
UPDATE: I create a service account and did not attach any kind of role to it. When I tried to login with this SA, It let me through and I was able to perform all kinds activities including deleting "secrets". So by default all SA are assuming admin access and that is the reason why my above roles are not working. Is this behavior expected, If yes then how can I change it?
A role binding grants the permissions defined in a role to a user or set of users. It holds a list of subjects (users, groups, or service accounts), and a reference to the role being granted. A RoleBinding grants permissions within a specific namespace whereas a ClusterRoleBinding grants that access cluster-wide.
Kubernetes service accounts let you give an identity to your Pods, which can be used to: Authenticate Pods to the Kubernetes API server, allowing the Pods to read and manipulate Kubernetes API objects (for example, a CI/CD pipeline that deploys applications to your cluster).
Service accounts are per namespace, so when done on a service account, any pods in that namespace that use this account will be affected by that setting.
Try the below steps
# create service account
kubectl create serviceaccount pod-viewer
# Create cluster role/role
---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: pod-viewer
rules:
- apiGroups: [""] # core API group
resources: ["pods", "namespaces"]
verbs: ["get", "watch", "list"]
---
# create cluster role binding
kubectl create clusterrolebinding pod-viewer \
--clusterrole=pod-viewer \
--serviceaccount=default:pod-viewer
# get service account secret
kubectl get secret | grep pod-viewer
pod-viewer-token-6fdcn kubernetes.io/service-account-token 3 2m58s
# get token
kubectl describe secret pod-viewer-token-6fdcn
Name: pod-viewer-token-6fdcn
Namespace: default
Labels: <none>
Annotations: kubernetes.io/service-account.name: pod-viewer
kubernetes.io/service-account.uid: bbfb3c4e-2254-11ea-a26c-0242ac110009
Type: kubernetes.io/service-account-token
Data
====
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZWNyZXQubmFtZSI6InBvZC12aWV3ZXItdG9rZW4tNmZkY24iLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC5uYW1lIjoicG9kLXZpZXdlciIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImJiZmIzYzRlLTIyNTQtMTFlYS1hMjZjLTAyNDJhYzExMDAwOSIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDpkZWZhdWx0OnBvZC12aWV3ZXIifQ.Pgco_4UwTCiOfYYS4QLwqgWnG8nry6JxoGiJCDuO4ZVDWUOkGJ3w6-8K1gGRSzWFOSB8E0l2YSQR4PB9jlc_9GYCFQ0-XNgkuiZBPvsTmKXdDvCNFz7bmg_Cua7HnACkKDbISKKyK4HMH-ShgVXDoMG5KmQQ_TCWs2E_a88COGMA543QL_BxckFowQZk19Iq8yEgSEfI9m8qfz4n6G7dQu9IpUSmVNUVB5GaEsaCIg6h_AXxDds5Ot6ngWUawvhYrPRv79zVKfAxYKwetjC291-qiIM92XZ63-YJJ3xbxPAsnCEwL_hG3P95-CNzoxJHKEfs_qa7a4hfe0k6HtHTWA
ca.crt: 1025 bytes
namespace: 7 bytes
```
Login to dashboard using the above token. you should see only pods and namespaces
[![Refer the below link][1]][1]
[1]: https://i.stack.imgur.com/D9bDi.png
Okay I've found the solution for this. The major issue was I'm running my cluster on Azure AKS, which I should have mentioned in the question but did not. It was my mistake. In Azure AKS, if rbac is not enabled during cluster creation, then there is no use of roles and role-bindings at all. All request to the api-server will be treated as requests from Admin. This was confirmed by Azure support too. So that was the reason my cluster-role-binding and roles didn't apply.
I see that the .yamls
you provided need some adjustments.
Role
has wrong formatting after the rules
part.
RoleBinding
is missing namespace:
after subjects:
, and also is formatted wrongly.
Try something like this:
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
namespace: assembly-prod
name: testreadrole
rules:
- apiGroups: [""]
resources: ["pods"]
verbs: ["get", "watch", "list"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: testrolebinding
namespace: assembly-prod
subjects:
- kind: ServiceAccount
name: testsa
namespace: assembly-prod
roleRef:
kind: Role
name: testreadrole
apiGroup: rbac.authorization.k8s.io
There is a very useful guide about Non-Privileged RBAC User Administration in Kubernetes where you can find more detailed info regarding this particular topic.
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