1.访问控制简介

2.创建sa账号

[root@server2 ~]# kubectl create serviceaccount admin   创建sa账号为admin
serviceaccount/admin created
[root@server2 ~]# kubectl get sa
NAME      SECRETS   AGE
admin     1         60s      admin创建成功
default   1         5d19h     
[root@server2 ~]# kubectl describe sa admin    查看admin账号详细信息
Name:                admin
Namespace:           default
Labels:              <none>
Annotations:         <none>
Image pull secrets:  <none>
Mountable secrets:   admin-token-fqlpn
Tokens:              admin-token-fqlpn           生成sa时会生成对应的token
Events:              <none>
[root@server2 secrets]# kubectl get secrets  查看secrets
NAME                  TYPE                                  DATA   AGE
admin-token-fqlpn     kubernetes.io/service-account-token   3      78m
default-token-zjzbf   kubernetes.io/service-account-token   3      5d21h
myregistrykey         kubernetes.io/dockerconfigjson        1      34s       myregistrykey为创建的secrets，里面存储的是镜像拉取认证信息
mysecret              Opaque                                2      57m
[root@server2 secrets]# kubectl patch serviceaccount admin -p '{"imagePullSecrets": [{"name": "myregistrykey"}]}'     
serviceaccount/admin patched    把myregistrykey放到了admin的sa账号，将myregistrykey和admin账号绑定，当admin账号创建pod时，会直接加载myregistrykey 里面的镜像拉取密钥信息
[root@server2 ~]# vim pod.yaml  创建pod
apiVersion: apps/v1
kind: Deployment
metadata:
  name: web-server
spec:
  selector:
    matchLabels:
      app: nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: reg.westos.org/westos/game2048:latest  指定私有仓库镜像
[root@server2 ~]# kubectl apply -f pod.yaml  创建
deployment.apps/web-server created
[root@server2 ~]# kubectl get pod   查看pod，运行pod失败
NAME                          READY   STATUS             RESTARTS   AGE
web-server-5bfd9b447f-7dz45   0/1     ImagePullBackOff   0          26s
[root@server2 ~]# kubectl describe pod web-server-5bfd9b447f-7dz45   查看pod详细信息

[root@server2 ~]# vim pod.yaml   

[root@server2 ~]# kubectl apply -f pod.yaml    创建
deployment.apps/web-server configured
[root@server2 ~]# kubectl get pod   查看pod，此时pod运行成功
NAME                         READY   STATUS    RESTARTS   AGE
web-server-5db5bbdc9-jpp2v   1/1     Running   0          59s

3.创建useraccount账号（用于登陆集群）

3.1 认证

[root@server2 ~]# kubectl delete -f pod.yaml  回收之前的
deployment.apps "web-server" deleted
[root@server2 ~]# kubectl config view   查看当前认证配置

[root@server2 ~]# cd /etc/kubernetes/
[root@server2 kubernetes]# cd pki/    这里面有很多的key和crt证书，创建自己生成的用户，需要相应的key和证书
apiserver.crt                 etcd
apiserver-etcd-client.crt     front-proxy-ca.crt
apiserver-etcd-client.key     front-proxy-ca.key
apiserver.key                 front-proxy-client.crt
apiserver-kubelet-client.crt  front-proxy-client.key
apiserver-kubelet-client.key  sa.key
ca.crt                        sa.pub
ca.key
[root@server2 pki]# openssl genrsa -out test.key 2048  创建test用户，需要生成test.key
Generating RSA private key, 2048 bit long modulus
......................................................................................................................................+++
..................................................+++
e is 65537 (0x10001)
[root@server2 pki]# openssl req -new -key test.key -out test.csr -subj "/CN=test"   生成证书请求
[root@server2 pki]# ll test.csr 
-rw-r--r-- 1 root root 883 Apr 17 06:57 test.csr  证书请求已经生成
[root@server2 pki]# openssl  x509 -req -in test.csr -CA ca.crt -CAkey ca.key  -CAcreateserial -out test.crt -days 365   拿着证书请求去申请证书，生成证书，有效期为365天
Signature ok
subject=/CN=test
Getting CA Private Key
[root@server2 pki]# ll test.crt    crt证书已经生成
-rw-r--r-- 1 root root 973 Apr 17 07:00 test.crt
[root@server2 pki]# openssl genrsa -out test.key 2048  查看证书信息
[root@server2 pki]# kubectl config set-credentials test --client-certificate=/etc/kubernetes/pki/test.crt --client-key=/etc/kubernetes/pki/test.key --embed-certs=true   需要把这些认证信息告诉k8s集群， 通过k8s客户端配置认证信息 ，用户test已经生成
User "test" set.
[root@server2 pki]# kubectl config set-context test@kubernetes --cluster=kubernetes --user=test
Context "test@kubernetes" created.
[root@server2 pki]# kubectl config set-context test@kubernetes --cluster=kubernetes --user=test  将test账号添加到	context里
[root@server2 pki]# kubectl config view  查看当前认证配置，可以发现test账号已经添加在context下

[root@server2 pki]# kubectl config use-context test@kubernetes  切换到test账号
Switched to context "test@kubernetes".
[root@server2 pki]# kubectl config view  查看认证配置

[root@server2 pki]# kubectl get pod   查看pod，发现列出pod资源没有权限，虽然认证通过了，但是没有任何权限
Error from server (Forbidden): pods is forbidden: User "test" cannot list resource "pods" in API group "" in the namespace "default"

3.2 授权：

RBAC（Role Based Access Control）：基于角色访问控制授权。
允许管理员通过Kubernetes API动态配置授权策略。RBAC就是用户通过角色与权限进行关联。
RBAC只有授权，没有拒绝授权，所以只需要定义允许该用户做什么即可。
RBAC包括四种类型：Role、ClusterRole、RoleBinding、ClusterRoleBinding。
角色有很多规则，相当于有很多权限，将用户和角色绑定，相当与给用户赋予了角色上的权限

3.2.1 创建角色

[root@server2 pki]# kubectl config use-context kubernetes-admin@kubernetes   先将用户切换到kubernetes-admin
[root@server2 ~]# mkdir rbac
[root@server2 ~]# cd rbac/
[root@server2 rbac]# vim role.yaml  创建角色
kind: Role                      
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  namespace: default
  name: myrole
rules:
- apiGroups: [""] 
  resources: ["pods"]   表示给了pod资源权限
  verbs: ["get", "watch", "list", "create", "update", "patch", "delete"]
[root@server2 rbac]# kubectl apply -f role.yaml   创建
role.rbac.authorization.k8s.io/myrole created
[root@server2 rbac]# kubectl get role  查看角色，创建成功
NAME     CREATED AT
myrole   2022-04-16T23:48:30Z

3.2.2 绑定角色

[root@server2 rbac]# vim role.yaml  
---
kind: RoleBinding        用户绑定角色
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: test-read-pods
  namespace: default    
subjects:
- kind: User
  name: test
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role               
  name: myrole      表示把myrole角色赋予test用户
  apiGroup: rbac.authorization.k8s.io
[root@server2 rbac]# kubectl apply -f role.yaml   创建
role.rbac.authorization.k8s.io/myrole unchanged
rolebinding.rbac.authorization.k8s.io/test-read-pods created
[root@server2 rbac]# kubectl get rolebindings.rbac.authorization.k8s.io 
NAME             ROLE          AGE
test-read-pods   Role/myrole   49s      可以发现test已经绑定了myrole这个角色
[root@server2 rbac]# kubectl config use-context test@kubernetes   切换到test用户
Switched to context "test@kubernetes".
[root@server2 rbac]# kubectl get pod  此时test用户访问pod资源是可以的
No resources found in default namespace.
[root@server2 rbac]# kubectl get sc  但是test用户访问别的资源是不可以的
Error from server (Forbidden): storageclasses.storage.k8s.io is forbidden: User "test" cannot list resource "storageclasses" in API group "storage.k8s.io" at the cluster scope
[root@server2 rbac]# kubectl get pod -n kube-system   指定别的kube-system  namespace  也不能访问，因为角色设置了指定的namespace为default
Error from server (Forbidden): pods is forbidden: User "test" cannot list resource "pods" in API group "" in the namespace "kube-system" 
[root@server2 rbac]# kubectl run demo --image=nginx  可以运行pod
pod/demo created
[root@server2 rbac]# kubectl get pod   可以查看pod
NAME   READY   STATUS    RESTARTS   AGE
demo   1/1     Running   0          26s
[root@server2 rbac]# kubectl delete pod demo   可以删除pod
pod "demo" deleted

3.2.3 设置集群角色以及集群角色绑定

[root@server2 rbac]# kubectl config use-context kubernetes-admin@kubernetes   切换到kubernetes-admin用户
[root@server2 rbac]# vim role.yaml
---                                                 创建集群角色
kind: ClusterRole                  
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: myclusterrole
rules:                       
- apiGroups: [""]
  resources: ["pods"]     有pod资源权限
  verbs: ["get", "watch", "list", "delete", "create", "update"]
- apiGroups: ["extensions", "apps"]
  resources: ["deployments"]      还有设置了deployments控制器权限
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]
---                  集群角色绑定
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding            
metadata:
  name: rolebind-myclusterrole
  namespace:  default                必须指定namespace，只针对指定的namespace
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole          
  name: myclusterrole        将集群角色赋予test用户
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: test
 [root@server2 rbac]# kubectl apply -f role.yaml   创建
role.rbac.authorization.k8s.io/myrole unchanged
rolebinding.rbac.authorization.k8s.io/test-read-pods unchanged
clusterrole.rbac.authorization.k8s.io/myclusterrole created
rolebinding.rbac.authorization.k8s.io/rolebind-myclusterrole created
[root@server2 rbac]# kubectl get rolebindings.rbac.authorization.k8s.io   查看角色绑定
NAME                     ROLE                        AGE
rolebind-myclusterrole   ClusterRole/myclusterrole   95s
test-read-pods           Role/myrole                 15h
 
 测试：
[root@server2 rbac]# kubectl config use-context test@kubernetes    切换到test账号
Switched to context "test@kubernetes".
[root@server2 rbac]# kubectl get pod -n kube-system   查看kube-system下的pod没有权限，因为指定的namespace是default
Error from server (Forbidden): pods is forbidden: User "test" cannot list resource "pods" in API group "" in the namespace "kube-system"
 [root@server2 rbac]# kubectl get deployments.apps    有查看控制器权限
No resources found in default namespace.

如何让用户操作整个集群的namespace

[root@server2 rbac]# kubectl config use-context kubernetes-admin@kubernetes    切换到kubernetes-admin
Switched to context "kubernetes-admin@kubernetes".
[root@server2 rbac]# vim role.yaml 
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding   通过ClusterRoleBinding绑定
metadata:
  name: clusterrolebinding-myclusterrole
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole                 通过ClusterRoleBinding这种方式绑定不需要指定namespace
  name: myclusterrole
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: User
  name: test
[root@server2 rbac]# kubectl apply -f role.yaml    再次创建
role.rbac.authorization.k8s.io/myrole unchanged
rolebinding.rbac.authorization.k8s.io/test-read-pods unchanged
clusterrole.rbac.authorization.k8s.io/myclusterrole unchanged
rolebinding.rbac.authorization.k8s.io/rolebind-myclusterrole unchanged
clusterrolebinding.rbac.authorization.k8s.io/clusterrolebinding-myclusterrole created
[root@server2 rbac]# kubectl config use-context test@kubernetes    切换到test用户
Switched to context "test@kubernetes".
[root@server2 rbac]# kubectl get pod -n kube-system   此时任何namespace下的pod都可以查看
NAME                              READY   STATUS    RESTARTS       AGE
coredns-7b56f6bc55-85s7v          1/1     Running   14 (29h ago)   7d2h
coredns-7b56f6bc55-b6n5x          1/1     Running   14 (29h ago)   7d2h
etcd-server2                      1/1     Running   11 (29h ago)   7d2h
kube-apiserver-server2            1/1     Running   11 (29h ago)   7d2h
kube-controller-manager-server2   1/1     Running   21 (29h ago)   7d2h
kube-flannel-ds-4hjs4             1/1     Running   0              31h
[root@server2 rbac]# kubectl get deployments.apps -n kube-system   可以任何namespace下的deployments控制器都可以查看
NAME      READY   UP-TO-DATE   AVAILABLE   AGE
coredns   2/2     2            2           7d2h

4. 补充

4.1 服务账户自动化

4.2 用户组的概念

4.3 集群预制角色

[root@server2 rbac]# kubectl get clusterrole   查看集群中有哪些角色
[root@server2 rbac]# kubectl describe clusterrole view   view表示集群中所有查看权限
[root@server2 rbac]# kubectl describe clusterrole edit     查看集群中的编辑权限
[root@server2 rbac]# kubectl describe clusterrole cluster-admin    查看集群管理员权限，比admin权限还大，可以操作所有资源
Name:         cluster-admin
Labels:       kubernetes.io/bootstrapping=rbac-defaults
Annotations:  rbac.authorization.kubernetes.io/autoupdate: true
PolicyRule:
  Resources  Non-Resource URLs  Resource Names  Verbs
  ---------  -----------------  --------------  -----
  *.*        []                 []              [*]
             [*]                []              [*]
注：这四个是集群预制的，可以直接使用