Kubernetes ---- RBAC授权管理

RBAC(授权插件)

RBAC基于角色访问控制: 

  许可: 对于任何一个被访问的对象(k8s组件),对于对象能施加的操作组合,将某些操作权限赋给角色,就完成了授权;
  角色: 可以让一个用户扮演一个角色,而这个角色拥有些权限,那么这个用户就拥有了这个角色的权限,权限授权给角色,与rolebinding工作在名称空间级别,授予名称空间范围内的许可权限的;
    operations: 允许角色做的操作,写进来就是说明允许,不能定义拒绝;
    subject: 对象,对哪些对象做哪些操作;
    rolebinding:
      将user account OR service account 绑定在哪个角色;
    clusterrole: 定义了角色允许的操作后, 与角色绑定的用户执行的操作位于集群,而不仅限于某个名称空间;
    clusterrolebinding: 将user account OR service account 绑定在哪个角色;

:
  user可通过rolebinding绑定clusterrole:
  所有操作依然是在名称空间范围内,当名称空间过多时,而且每个名称空间都需要一个管理员,直接定义一个clusterrole使用rolebinding就相当于每个用户都是在自己的名称空间中操作的,如果不用这种
  方法的话,有N个名称空间就要创建N个role,N个rolebinding;

创建角色:

$ 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创建并绑定:

$ 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
# 发现之前创建的用户已经有了查看pods的权限;
$ 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创建并绑定:

$ 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 
....

绑定:

$ 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
# 绑定后发现所有名称空间的deployment与pods资源都可以查看(get,list,watch)
$ kubectl get pods && kubectl get pods -n kube-system
$ kubectl get deploy && kubectl get deploy -n kube-system
使用rolebinding绑定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

 

 
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