K8S创建用户RBAC授权

目录

Kubernetes操作账号及权限设置

目前RBAC是k8s授权方式最常用的一种方式。在k8s上，一个客户端向apiserver发起请求，需要如下信息：

1）username，uid，
2) group,
3) extra(额外信息)
4) API
5) request path,例如：http:``//127.0.0.1:8080/apis/apps/v1/namespaces/kube-system/d
6）HTTP request action，如get,post,put,``delete``,
7）Http request action，如 get,list,create,udate,patch,watch,proxy,redirect,``delete``,deletecollection
8） Rresource
9）Subresource
10）Namespace
11）API group

创建serviceaccount

# In GKE need to get RBAC permissions first with
# kubectl create clusterrolebinding cluster-admin-binding --clusterrole=cluster-admin [--user=<user-name>|--group=<group-name>]

---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: jenkins
  namespace：jenkins

---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: jenkins
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["create","delete","get","list","patch","update","watch"]
- apiGroups: [""]
  resources: ["pods/exec"]
  verbs: ["create","delete","get","list","patch","update","watch"]
- apiGroups: [""]
  resources: ["pods/log"]
  verbs: ["get","list","watch"]
- apiGroups: [""]
  resources: ["events"]
  verbs: ["watch"]
- apiGroups: [""]
  resources: ["secrets"]
  verbs: ["get"]

---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: RoleBinding
metadata:
  name: jenkins
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: Role
  name: jenkins
subjects:
- kind: ServiceAccount
  name: jenkins

创建useraccount

一．生成账号

例如：给K8S集群创建一个gpu用户

在k8s的master节点上执行：

#创建证书
(umask 077; openssl genrsa -out gpu.key 2048) 
openssl req -new -key gpu.key -out gpu.csr -subj "/CN=gpu"
openssl x509 -req -in gpu.csr -CA /etc/kubernetes/pki/ca.crt -CAkey /etc/kubernetes/pki/ca.key -CAcreateserial -out gpu.crt -days 3650
openssl x509 -in gpu.crt -text -noout

#把用户账户信息添加到k8s集群中
kubectl config set-credentials gpu --client-certificate=./gpu.crt --client-key=./gpu.key --embed-certs=true

#创建账户，设置用户访问的集群
kubectl config set-context gpu@kubernetes --cluster=kubernetes --user=gpu

#切换用户
kubectl config use-context gpu@kubernetes
#验证权限
kubectl get pods
#切换成管理员
kubectl config use-context kubernetes-admin@kubernetes	


查看所有用户
kubectl config get-contexts

查看集群角色
kubectl get ClusterRole

查看服务账户
kubectl get serviceAccount

二．设置权限

在管理员权限下创建角色和权限并绑定到用户（role 和role-binding）

role.yaml

kind: Role
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  namespace: gpu
  name: gpu-reader
rules:
rules:
  - apiGroups: [""] # "" indicates the core API group
    resources: ["services"]
    verbs: ["get", "watch", "list"]
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get"]
  - apiGroups: ["batch", "externsions"]
    resources: ["jobs"]
    verbs: ["get","list","watch","create", "update","patch","delete"]

role-binding.yaml

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
  name: read-pods
  namespace: gpu
subjects:
- kind: User
  name: gpu
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: gpu-reader
  apiGroup: rbac.authorization.k8s.io

三．生成用户config文件

输出全部用户配置

kubectl config view --raw --output='json' >1.json
vim 1.json
删除users内除"name": "gpu"的其他内容
删除contexts内除"name": "gpu@kubernetes"的其他内容

mv 1.json config //分发config给用户

RBAC

一、基于角色的访问控制

rbac:role based ac，也就是我们把用户加入角色里面，这样用户就具有角色的权限了。

RBAC是通过rolebinding把user绑定到role上的。而role是基于namespace设定的，也就是这说这个user只能访问指定namespace下的pod资源。

而如果把user通过ClusterRoleBind绑定到ClusterRole上后，那么这个user就突破了namespace的限制，而拥有了集群级别的权限，即这个用户可以访问这个集群下所有namespace下的pod了。

但是，我们也可以用RoleBinding去把user绑定到ClusteRrole。在下图中，我们把user1通过rolebinding绑定到ClusteRrole上，但是我们知道rolebinding只限制在namespace中，所以user1也只限定在namespace中，而不是整个集群中。

二、CluserRoleBinding和RoleBinding的区别

CluserRoleBinding是针对集群的，而RoleBinding是只针对namespace的。

三、useraccount和serviceaccount

k8s验证分为useraccount和serviceaccount。

个人理解serviceaccount是指服务账户，是指在POD的启动账户，serviceaccount设置的就是该POD启动后的权限。比如linux服务器下httpd服务可以指定http账户启动，但http账户本身没有对系统的登录权限。

useraccount就好比是linux服务器的登录账户，是有登录权限的。可以使用confi在客户端连接K8S集群的账户。

附录

一、使用create生成配置的yaml文件

kubectl create serviceaccount mysa -o yaml --dry-run > mysa.yaml

上面我们可以看到，只要是kubectl create的，只要加上-o yaml，就可以导出清单文件，这样我们以后就不用从头到尾写清单文件了，而是只要生产一个，然后改改就行了，这个很不错。

另外kubectl get 也可以导出yaml格式的，如下：

kubectl get pods myapp``-1` `-o yaml --export

二、创建jenkins的serviceaccount

kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  namespace: jenkins
  name: service-reader
rules:
  - apiGroups: [""] # "" indicates the core API group
    resources: ["services"]
    verbs: ["get", "watch", "list"]
  - apiGroups: [""]
    resources: ["pods"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/exec"]
    verbs: ["create","delete","get","list","patch","update","watch"]
  - apiGroups: [""]
    resources: ["pods/log"]
    verbs: ["get","list","watch"]
  - apiGroups: [""]
    resources: ["secrets"]
    verbs: ["get"]

#在jenkins命名空间下创建一个服务账号jenkins
#kubectl create serviceaccount jenkins -n jenkins -o yaml
kubectl create serviceaccount jenkins -n servers

#创建一个名为“service-reader-pod”的集群角色绑定，它的“clusterrole”是“service-reader”，它的名字是“default:default”，其中第一个“default”是名空间（namespace），第二个“default”是服务账户名字

kubectl create clusterrolebinding service-reader-pod --clusterrole=service-reader  --serviceaccount=servers:jenkins

参考文献

http://blog.itpub.net/28916011/viewspace-2215100/

posted @ 2020-09-25 18:06  名字很长容易被惦记  阅读(2733)  评论(0)  编辑  收藏  举报