如何设置 kubernetes RBAC 资源，以便 pod 可以通过客户端访问 API？

Question

问题

我有一个简单的 RBAC 配置来访问集群内的 Kubernetes API。但是，我从kubectl 得到了似乎相互矛盾的信息。部署清单后，RBAC 似乎设置正确。

$ kubectl exec -ti pod/controller -- kubectl auth can-i get namespaces
Warning: resource 'namespaces' is not namespace scoped
yes

但是，实际发出请求会产生权限错误

$ kubectl exec -ti pod/controller -- kubectl get namespaces
Error from server (Forbidden): namespaces is forbidden: User "system:serviceaccount:default:controller" cannot list resource "namespaces" in API group "" at the cluster scope
command terminated with exit code 1

清单

apiVersion: 'v1'
kind: 'ServiceAccount'
metadata:
  name: 'controller'
---

apiVersion: 'rbac.authorization.k8s.io/v1'
kind: 'Role'
metadata:
  name: 'read-namespaces'
rules:
  - apiGroups:
      - ''
    resources:
      - 'namespaces'
    verbs:
      - 'get'
      - 'watch'
      - 'list'
---

apiVersion: 'rbac.authorization.k8s.io/v1'
kind: 'RoleBinding'
metadata:
  name: 'read-namespaces'
roleRef:
  apiGroup: ''
  kind: 'Role'
  name: 'read-namespaces'
subjects:
  - kind: 'ServiceAccount'
    name: 'controller'
---

apiVersion: 'v1'
kind: 'Pod'
metadata:
  name: 'controller'
  labels:
    'app': 'controller'
spec:
  containers:
    - name: 'kubectl'
      image: 'bitnami/kubectl:latest'
      imagePullPolicy: 'Always'
      command:
        - 'sleep'
        - '3600'
  serviceAccountName: 'controller'
---

其他信息

我试过kubectl auth reconcile -f manifest.yaml和kubectl apply -f manifest.yaml，结果都是一样的。

我还将“read-namespaces”RoleBinding.subjects[0].namespace 设置为正确的命名空间（在本例中为“默认”）。输出没有变化。

Answer 1

命名空间是集群范围的资源。所以你需要一个ClusterRole 和一个ClusterRoleBinding。

apiVersion: 'rbac.authorization.k8s.io/v1'
kind: 'ClusterRole'
metadata:
  name: 'read-namespaces'
rules:
  - apiGroups:
      - ''
    resources:
      - 'namespaces'
    verbs:
      - 'get'
      - 'watch'
      - 'list'
---

apiVersion: 'rbac.authorization.k8s.io/v1'
kind: 'ClusterRoleBinding'
metadata:
  name: 'read-namespaces'
roleRef:
  apiGroup: 'rbac.authorization.k8s.io'
  kind: 'ClusterRole'
  name: 'read-namespaces'
subjects:
  - kind: 'ServiceAccount'
    name: 'controller'
--- 

Answer 2

角色是每个命名空间的，您需要使用ClusterRoleBinding创建集群角色和绑定

如果你想将你的集群角色绑定到特定的命名空间，你可以这样做，在 ClusterRole 上使用 RoleBinding：

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: sa
  namespace: myapp

---
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: role-myapp
rules:
- apiGroups:
  - batch
  resources:
  - cronjobs
  verbs:
  - create
  - delete
  - deletecollection
  - get
  - list
  - patch
  - update
  - watch

---

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: job001
  namespace: myapp
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: role-myapp
subjects:
- kind: ServiceAccount
  name: sa
  namespace: myapp