RBAC(授權插件)
RBAC基於角色訪問控制:
許可: 對於任何一個被訪問的對象(k8s組件),對於對象能施加的操作組合,將某些操作權限賦給角色,就完成了授權;
角色: 可以讓一個用戶扮演一個角色,而這個角色擁有些權限,那麼這個用戶就擁有了這個角色的權限,權限授權給角色,與rolebinding工作在名稱空間級別,授予名稱空間範圍內的許可權限的;
operations: 允許角色做的操作,寫進來就是說明允許,不能定義拒絕;
subject: 對象,對哪些對象做哪些操作;
rolebinding:
將user account OR service account 綁定在哪個角色;
clusterrole: 定義了角色允許的操作後, 與角色綁定的用戶執行的操作位於集羣,而不僅限於某個名稱空間;
clusterrolebinding: 將user account OR service account 綁定在哪個角色;
注:
user可通過rolebinding綁定clusterrole:
所有操作依然是在名稱空間範圍內,當名稱空間過多時,而且每個名稱空間都需要一個管理員,直接定義一個clusterrole使用rolebinding就相當於每個用戶都是在自己的名稱空間中操作的,如果不用這種
方法的話,有N個名稱空間就要創建N個role,N個rolebinding;
創建角色:
$ kubectl create role --help
Usage:
kubectl create role NAME --verb=verb --resource=resource.group/subresource [--resource-name=resourcename] [--dry-run]
$ kubectl create role pod-reader --verb=get,list,watch --resource=pods --dry-run -o yaml > role-demo.yaml
$ vim role-demo.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: pod-reader
namespace: default
rules:
- apiGroups:
- ""
resources:
- pods
verbs:
- get
- list
- watch
$ kubectl get role
NAME AGE
pod-reader 39s
$ kubectl describe role pod-reader
....
PolicyRule:
Resources Non-Resource URLs Resource Names Verbs
--------- ----------------- -------------- -----
pods [] [] [get list watch]
rolebinding創建並綁定:
$ kubectl create rolebinding --help
Usage:
kubectl create rolebinding NAME --clusterrole=NAME|--role=NAME [--user=username] [--group=groupname]
[--serviceaccount=namespace:serviceaccountname] [--dry-run] [options]
$ kubectl create rolebinding kfree-read-pods --role=pod-reader --user=kfree --dry-run -o yaml > rolebinding-demo.yaml
$ vim rolebinding-demo.yaml
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: kfree-read-pods
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: pod-reader
subjects:
- apiGroup: rbac.authorization.k8s.io
kind: User
name: kfree
$ kubectl config use-context kfree@kubernetes
# 發現之前創建的用戶已經有了查看pods的權限;
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
deploy-demo-854b57c687-4hbp4 1/1 Running 0 5h26m
deploy-demo-854b57c687-f7txr 1/1 Running 0 5h26m
deploy-demo-854b57c687-t9bbl 1/1 Running 0 5h26m
clusterrole創建並綁定:
$ kubectl create clusterrole --help
Usage:
kubectl create clusterrole NAME --verb=verb --resource=resource.group [--resource-name=resourcename] [--dry-run]
$ kubectl create clusterrole cluster-readers --verb=get,list,watch --resource=pods,deployment --dry-run -o yaml > clusterrole-demo.yaml
$ kubectl apply -f clusterrole-demo.yaml
$ kubectl get clusterrole
....
cluster-readers
....
綁定:
$ kubectl create clusterrolebinding --help
Usage:
kubectl create clusterrolebinding NAME --clusterrole=NAME [--user=username] [--group=groupname]
[--serviceaccount=namespace:serviceaccountname] [--dry-run] [options]
$ kubectl create clusterrolebinding kfree-read-all-pods --clusterrole=cluster-readers --user=kfree --dry-run -o yaml > clusterrolebinding-demo.yaml
$ kubectl apply -f clusterrolebinding-demo.yaml
$ kubectl config use-context kfree@kubernetes
# 綁定後發現所有名稱空間的deployment與pods資源都可以查看(get,list,watch)
$ kubectl get pods && kubectl get pods -n kube-system
$ kubectl get deploy && kubectl get deploy -n kube-system
使用rolebinding綁定clusterrole:
$ kubectl delete clusterrolebinding kfree-read-all-pods
$ kubectl create rolebinding kfree-read-pods --clusterrole=cluster-readers --user=kfree --dry-run -o yaml > rolebinding-clusterrole-demo.yaml
$ kubectl apply -f rolebinding-clusterrole-demo.yaml
$ kubectl get rolebinding
NAME AGE
kfree-read-pods 3m
$ kubectl config view
....
current-context: kfree@kubernetes
....
$ kubectl get pods -n kube-system
Error from server (Forbidden): pods is forbidden: User "kfree" cannot list resource "pods" in API group "" in the namespace "kube-system"
$ kubectl get pods
NAME READY STATUS RESTARTS AGE
deploy-demo-854b57c687-4hbp4 1/1 Running 1 18h
deploy-demo-854b57c687-f7txr 1/1 Running 1 18h
deploy-demo-854b57c687-t9bbl 1/1 Running 1 18h