k8s RBAC 多租户权限控制实现
访问到权限分两部分
1.Authenticating认证
授权配置由kube-apiserver管理
这里使用的是 Static Password File 方式。
apiserver启动yaml里配置basic-auth-file即可，容器 启动apiserver的话要注意这个文件需要是在容器内能访问到的。（可以通过挂载文件，或者在已经挂载的路径里增加配置文件）
basic-auth-file文件格式见官方文档https://kubernetes.io/docs/admin/authentication/#static-password-file 注意password在第一个，之前没注意被卡了很久。
修改了文件以后需要重启apiserver才能生效。这里kubectl delete 删除pod有问题，使用docker命令查看apiserver容器其实没有重启。解决方案是使用docker kill杀掉容器。自动重启。
[root@tensorflow1 ~]# curl -u admin:admin "https://localhost:6443/api/v1/pods" -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "pods is forbidden: User \"system:anonymous\" cannot list pods at the cluster scope",
"reason": "Forbidden",
"details": {
"kind": "pods"
},
"code": 403
}
这个就是没有通过认证的报错
2.Authorization授权
k8s RBAC授权规则
https://kubernetes.io/docs/admin/authorization/rbac/
简单来说就是 权限--角色--用户绑定
需要配置两个文件
一个是role/clusterRole，定义角色以及其权限
一个是roleBinding/clusterRoleBinding，定义用户和角色的关系
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "pods is forbidden: User \"admin\" cannot list pods at the cluster scope",
"reason": "Forbidden",
"details": {
"kind": "pods"
},
"code": 403
}
这个就是没有权限访问，需要配置RBAC
文件如下：
方案1：role + roleBinding
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
namespace: user1
name: pod-reader
rules:
- apiGroups: [""] # "" indicates the core API group
resources: ["pods"]
verbs: ["*"]
- apiGroups: [""] # "" indicates the core API group
resources: ["namespaces"]
verbs: ["*"]
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: user1-rolebinding
namespace: user1
subjects:
- kind: User
name: user1 # Name is case sensitive
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: myauth-user
apiGroup: rbac.authorization.k8s.io
方案2：clusterRole + roleBinding （推荐）
clusterRole定义全局权限，roleBinding将权限限制到namespace。clusterRole仅需要定义一次。
kind: ClusterRole
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: myauth-user
rules:
- apiGroups: [""] # "" indicates the core API group
resources: ["pods"]
verbs: ["*"]
- apiGroups: [""] # "" indicates the core API group
resources: ["namespaces"]
verbs: ["*"]
- apiGroups: [""] # "" indicates the core API group
resources: ["resourcequotas"]
verbs: ["*"]
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: user2-rolebinding
namespace: user2
subjects:
- kind: User
name: user2 # Name is case sensitive
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: myauth-user
apiGroup: rbac.authorization.k8s.io
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
name: user1-rolebinding
namespace: user1
subjects:
- kind: User
name: user1 # Name is case sensitive
apiGroup: rbac.authorization.k8s.io
roleRef:
kind: ClusterRole
name: myauth-user
apiGroup: rbac.authorization.k8s.io
3.配置
新建静态密码文件
# vi /etc/kubernetes/pki/basic_auth_file
admin,admin,1004
jane2,jane,1005
user1,user1,1006
user2,user2,1007
修改apiserver配置
修改/etc/kubernetes/manifests/kube-apiserver.yaml
在一堆参数配置下面增加
- --basic-auth-file=/etc/kubernetes/pki/basic_auth_file
eg:
- --etcd-servers=https://127.0.0.1:2379
- --etcd-cafile=/etc/kubernetes/pki/etcd/ca.crt
- --etcd-certfile=/etc/kubernetes/pki/apiserver-etcd-client.crt
- --etcd-keyfile=/etc/kubernetes/pki/apiserver-etcd-client.key
- --basic-auth-file=/etc/kubernetes/pki/basic_auth_file
这里将静态文件放在/etc/kubernetes/pki/目录下的原因是，apiserver通过容器启动，这个路径已经挂载容器中了，可以被访问到。放在其他路径需要额外配置挂载路径。apiserver只会启动在master节点上，故仅需要在master节点上配置即可。
启动好以后在master机器上执行kubectl get all，多半是执行不成功的，因为修改apiserver配置文件后，apiserver自动重启，然后启动失败，所以就无法访问集群了。
使用docker ps 查看发现k8s_kube-scheduler 和k8s_kube-controller-manager重启了，但是apiserver没起来。
执行systemctl restart kubelet，再docker ps 就能看到apiserver启动成功了。如果还没启动起来，那再看看上面哪里配置有问题。
应用
使用--username={username} --password={password} 参数访问kubectl
参考https://kubernetes-v1-4.github.io/docs/user-guide/kubectl/kubectl_create/
kubectl get all -n user1 --username=user1 --password=user1
kubectl create -f tf1-rc.yaml --username=user1 --password=user1
使用 curl -u {username}:{password} `js
"https://{masterIP}:6443/api/v1/" -k 访问http restful api
curl -u jane:jane2 "https://localhost:6443/api/v1/namespaces/user1/pods" -k
curl -u jane:jane2 "https://localhost:6443/api/v1/namespaces/user1" -k
curl -u user1:user1 "https://localhost:6443/api/v1/namespaces/user1" -k
curl -u user1:user1 "https://localhost:6443/api/v1/namespaces/user1/pods" -k
curl -u user1:user1 "https://localhost:6443/api/v1/namespaces/user1/resourcequotas/" -k
curl -u user2:user2 "https://localhost:6443/api/v1/namespaces/user2" -k
curl -u user2:user2 "https://localhost:6443/api/v1/namespaces/user2/pods" -k
curl -u user2:user2 "https://localhost:6443/api/v1/namespaces/user2/resourcequotas/" -k
