在k8s的集群中对于资源对象的操作都是通过 APIServer 进行的，那么集群是怎样知道我们的请求就是合法的请求呢？这个就需要了解 Kubernetes 中另外一个非常重要的知识点了：RBAC（基于角色的权限控制）。

管理员可以通过 Kubernetes API 动态配置策略来启用RBAC，需要在 kube-apiserver 中添加参数--authorization-mode=RBAC

查看静态pod，kube-api的yaml文件,如下：

[root@master ~]# cat  /etc/kubernetes/manifests/kube-apiserver.yaml | grep -i rbac
    - --authorization-mode=Node,RBAC
[root@master ~]# 
[root@master ~]# 

API对象

在 Kubernetes 集群中，Kubernetes 对象是我们持久化的实体，就是最终存入 etcd 中的数据，集群中通过这些实体来表示整个集群的状态。

Kubernetes API 是一个以 JSON 为主要序列化方式的 HTTP 服务，除此之外也支持 Protocol Buffers 序列化方式，主要用于集群内部组件间的通信。为了可扩展性，Kubernetes 在不同的 API 路径（比如/api/v1 或者 /apis/batch）下面支持了多个 API 版本，不同的 API 版本意味着不同级别的稳定性和支持：

• Alpha 级别，例如 v1alpha1 默认情况下是被禁用的，可以随时删除对功能的支持，所以要慎用

• Beta 级别，例如 v2beta1 默认情况下是启用的，表示代码已经经过了很好的测试，但是对象的语义可能会在随后的版本中以不兼容的方式更改

• 稳定级别，比如 v1 表示已经是稳定版本了，也会出现在后续的很多版本中。
  在 Kubernetes 集群中，一个 API 对象在 Etcd 里的完整资源路径，是由：Group（API 组）、Version（API 版本）和 Resource（API 资源类型）三个部分组成的。

如下可以看到集群中的api形式：

[root@master ~]# kubectl get --raw /
{
  "paths": [
    "/.well-known/openid-configuration",
    "/api",
    "/api/v1",
    "/apis",
    "/apis/",
    "/apis/admissionregistration.k8s.io",
    "/apis/admissionregistration.k8s.io/v1",
    "/apis/apiextensions.k8s.io",
    "/apis/apiextensions.k8s.io/v1",
    "/apis/apiregistration.k8s.io",
    "/apis/apiregistration.k8s.io/v1",
    "/apis/apps",
    "/apis/apps/v1",
    "/apis/authentication.k8s.io",
    "/apis/authentication.k8s.io/v1",
    "/apis/authorization.k8s.io",
    "/apis/authorization.k8s.io/v1",
    "/apis/autoscaling",
    "/apis/autoscaling/v1",
    "/apis/autoscaling/v2",
    "/apis/autoscaling/v2beta2",
    "/apis/batch",
    "/apis/batch/v1",
    "/apis/certificates.k8s.io",
    "/apis/certificates.k8s.io/v1",
    "/apis/coordination.k8s.io",
    "/apis/coordination.k8s.io/v1",
    "/apis/crd.projectcalico.org",
    "/apis/crd.projectcalico.org/v1",
    "/apis/discovery.k8s.io",
    "/apis/discovery.k8s.io/v1",
    "/apis/events.k8s.io",
    "/apis/events.k8s.io/v1",
    "/apis/flowcontrol.apiserver.k8s.io",
    "/apis/flowcontrol.apiserver.k8s.io/v1beta1",
    "/apis/flowcontrol.apiserver.k8s.io/v1beta2",
    "/apis/metrics.k8s.io",
    "/apis/metrics.k8s.io/v1beta1",
    "/apis/networking.k8s.io",
    "/apis/networking.k8s.io/v1",
    "/apis/node.k8s.io",
    "/apis/node.k8s.io/v1",
    "/apis/policy",
    "/apis/policy/v1",
    "/apis/rbac.authorization.k8s.io",
    "/apis/rbac.authorization.k8s.io/v1",
    "/apis/scheduling.k8s.io",
    "/apis/scheduling.k8s.io/v1",
    "/apis/storage.k8s.io",
    "/apis/storage.k8s.io/v1",
    "/apis/storage.k8s.io/v1beta1",
    "/healthz",
    "/healthz/autoregister-completion",
    "/healthz/etcd",
    "/healthz/log",
    "/healthz/ping",
    "/healthz/poststarthook/aggregator-reload-proxy-client-cert",
    "/healthz/poststarthook/apiservice-openapi-controller",
    "/healthz/poststarthook/apiservice-openapiv3-controller",
    "/healthz/poststarthook/apiservice-registration-controller",
    "/healthz/poststarthook/apiservice-status-available-controller",
    "/healthz/poststarthook/bootstrap-controller",
    "/healthz/poststarthook/crd-informer-synced",
    "/healthz/poststarthook/generic-apiserver-start-informers",
    "/healthz/poststarthook/kube-apiserver-autoregistration",
    "/healthz/poststarthook/priority-and-fairness-config-consumer",
    "/healthz/poststarthook/priority-and-fairness-config-producer",
    "/healthz/poststarthook/priority-and-fairness-filter",
    "/healthz/poststarthook/rbac/bootstrap-roles",
    "/healthz/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/healthz/poststarthook/start-apiextensions-controllers",
    "/healthz/poststarthook/start-apiextensions-informers",
    "/healthz/poststarthook/start-cluster-authentication-info-controller",
    "/healthz/poststarthook/start-kube-aggregator-informers",
    "/healthz/poststarthook/start-kube-apiserver-admission-initializer",
    "/healthz/poststarthook/storage-object-count-tracker-hook",
    "/livez",
    "/livez/autoregister-completion",
    "/livez/etcd",
    "/livez/log",
    "/livez/ping",
    "/livez/poststarthook/aggregator-reload-proxy-client-cert",
    "/livez/poststarthook/apiservice-openapi-controller",
    "/livez/poststarthook/apiservice-openapiv3-controller",
    "/livez/poststarthook/apiservice-registration-controller",
    "/livez/poststarthook/apiservice-status-available-controller",
    "/livez/poststarthook/bootstrap-controller",
    "/livez/poststarthook/crd-informer-synced",
    "/livez/poststarthook/generic-apiserver-start-informers",
    "/livez/poststarthook/kube-apiserver-autoregistration",
    "/livez/poststarthook/priority-and-fairness-config-consumer",
    "/livez/poststarthook/priority-and-fairness-config-producer",
    "/livez/poststarthook/priority-and-fairness-filter",
    "/livez/poststarthook/rbac/bootstrap-roles",
    "/livez/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/livez/poststarthook/start-apiextensions-controllers",
    "/livez/poststarthook/start-apiextensions-informers",
    "/livez/poststarthook/start-cluster-authentication-info-controller",
    "/livez/poststarthook/start-kube-aggregator-informers",
    "/livez/poststarthook/start-kube-apiserver-admission-initializer",
    "/livez/poststarthook/storage-object-count-tracker-hook",
    "/logs",
    "/metrics",
    "/openapi/v2",
    "/openapi/v3",
    "/openapi/v3/",
    "/openid/v1/jwks",
    "/readyz",
    "/readyz/autoregister-completion",
    "/readyz/etcd",
    "/readyz/etcd-readiness",
    "/readyz/informer-sync",
    "/readyz/log",
    "/readyz/ping",
    "/readyz/poststarthook/aggregator-reload-proxy-client-cert",
    "/readyz/poststarthook/apiservice-openapi-controller",
    "/readyz/poststarthook/apiservice-openapiv3-controller",
    "/readyz/poststarthook/apiservice-registration-controller",
    "/readyz/poststarthook/apiservice-status-available-controller",
    "/readyz/poststarthook/bootstrap-controller",
    "/readyz/poststarthook/crd-informer-synced",
    "/readyz/poststarthook/generic-apiserver-start-informers",
    "/readyz/poststarthook/kube-apiserver-autoregistration",
    "/readyz/poststarthook/priority-and-fairness-config-consumer",
    "/readyz/poststarthook/priority-and-fairness-config-producer",
    "/readyz/poststarthook/priority-and-fairness-filter",
    "/readyz/poststarthook/rbac/bootstrap-roles",
    "/readyz/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/readyz/poststarthook/start-apiextensions-controllers",
    "/readyz/poststarthook/start-apiextensions-informers",
    "/readyz/poststarthook/start-cluster-authentication-info-controller",
    "/readyz/poststarthook/start-kube-aggregator-informers",
    "/readyz/poststarthook/start-kube-apiserver-admission-initializer",
    "/readyz/poststarthook/storage-object-count-tracker-hook",
    "/readyz/shutdown",
    "/version"
  ]
}[root@master ~]# 

也可以通过 kubectl 来查询对应对象下面的数据：

[root@master ~]#  kubectl get --raw /api/v1 | python -m json.tool  |more
{
    "groupVersion": "v1",
    "kind": "APIResourceList",
    "resources": [
        {
            "kind": "Binding",
            "name": "bindings",
            "namespaced": true,
            "singularName": "",
            "verbs": [
                "create"
            ]
        },
        {
            "kind": "ComponentStatus",
            "name": "componentstatuses",
            "namespaced": false,
            "shortNames": [
                "cs"
            ],
            "singularName": "",
            "verbs": [
                "get",
                "list"
            ]
        },
        {
            "kind": "ConfigMap",
            "name": "configmaps",
            "namespaced": true,
            "shortNames": [
                "cm"
            ],
            "singularName": "",
            "storageVersionHash": "qFsyl6wFWjQ=",
            "verbs": [
                "create",
                "delete",
                "deletecollection",
                "get",
                "list",
                "patch",
                "update",
                "watch"
            ]
        },
        {
            "kind": "Endpoints",
            "name": "endpoints",
            "namespaced": true,
            "shortNames": [
                "ep"
            ],
            "singularName": "",
            "storageVersionHash": "fWeeMqaN/OA=",
            "verbs": [
                "create",
                "delete",
                "deletecollection",
                "get",
                "list",
                "patch",
                "update",
                "watch"
            ]
        },
        {
            "kind": "Event",
            "name": "events",
            "namespaced": true,
            "shortNames": [
                "ev"
            ],
            "singularName": "",
            "storageVersionHash": "r2yiGXH7wu8=",
            "verbs": [
                "create",
                "delete",
                "deletecollection",
                "get",
                "list",
                "patch",
                "update",
                "watch"
            ]
        },
        {
            "kind": "LimitRange",
            "name": "limitranges",
            "namespaced": true,
            "shortNames": [
                "limits"
            ],
            "singularName": "",
            "storageVersionHash": "EBKMFVe6cwo=",
            "verbs": [
                "create",
                "delete",
                "deletecollection",
                "get",
                "list",
                "patch",
                "update",
                "watch"
            ]
        },
        {
            "kind": "Namespace",
            "name": "namespaces",
            "namespaced": false,
            "shortNames": [
                "ns"
            ],
            "singularName": "",
            "storageVersionHash": "Q3oi5N2YM8M=",
            "verbs": [
                "create",
                "delete",
                "get",
                "list",
                "patch",
                "update",
                "watch"
            ]
.......................
.......................

通常，Kubernetes API 支持通过标准 HTTP POST、PUT、DELETE 和 GET 在指定 PATH 路径上创建、更新、删除和检索操作，并使用 JSON 作为默认的数据交互格式。

比如下面创建一个pod

apiVersion: apps/v1
kind: deployment

其中 Deployment 就是这个 API 对象的资源类型（Resource），apps 就是它的组（Group），v1 就是它的版本（Version）。API Group、Version 和 资源就唯一定义了一个 HTTP 路径，然后在 kube-apiserver 端对这个 url 进行了监听，然后把对应的请求传递给了对应的控制器进行处理。

RBAC

上面我们介绍了 Kubernetes 所有资源对象都是模型化的 API 对象，允许执行 CRUD(Create、Read、Update、Delete) 操作，比如下面的这些资源类型：

pods
deployment
service
deamonset
secret
configmap
........

对于上述之源可以进行如下操作：

create
get 
list
delete
update
watch
patch
edit
..........

在往上层，这些资源和 API Group 进行关联，比如 Pods 属于 Core API Group，而 Deployements 属于 apps API Group，现在我们要在 Kubernetes 中通过 RBAC 来对资源进行权限管理，除了上面的这些资源和操作以外，我们还需要了解另外几个概念：

• Rule：规则，规则是一组属于不同 API Group 资源上的一组操作的集合

• Role 和 ClusterRole：角色和集群角色，这两个对象都包含上面的 Rules 元素，二者的区别在于，在 Role 中，定义的规则只适用于单个命名空间，而 ClusterRole 是集群范围内的，定义的规则不受命名空间的约束。

• Subject：主题，对应集群中尝试操作的对象，集群中定义了3种类型的主题资源：

  • User Account：用户，这是有外部独立服务进行管理的，管理员进行私钥的分配，用户可以使用 KeyStone 或者 Goolge 帐号，甚至一个用户名和密码的文件列表也可以。对于用户的管理集群内部没有一个关联的资源对象，所以用户不能通过集群内部的 API 来进行管理
  • Group：组，这是用来关联多个账户的，集群中有一些默认创建的组，比如 cluster-admin
  • Service Account：服务帐号，通过 Kubernetes API 来管理的一些用户帐号，和 namespace 进行关联的，适用于集群内部运行的应用程序，需要通过 API 来完成权限认证，所以在集群内部进行权限操作，我们都需要使用到 ServiceAccount

• RoleBinding 和 ClusterRoleBinding：角色绑定和集群角色绑定，简单来说就是把声明的 Subject 和我们的 Role 进行绑定的过程（给某个用户绑定上操作的权限），二者的区别也是作用范围的区别：RoleBinding 只会影响到当前 namespace 下面的资源操作权限，而 ClusterRoleBinding 会影响到所有的 namespace。

示例测试

• 创建访问单个ns的serviceaccount账户

1：创建sa,编辑yaml文件如下：
apiVersion: v1
kind: ServiceAccount
metadata:
  name: sa-test
  namespace: kube-system


[root@master rbac]# kubectl apply -f  sa.yaml
serviceaccount/sa-test created
[root@master rbac]# 
[root@master rbac]# kubectl get sa -n kube-system  | grep sa-test
sa-test                              0         18s
[root@master rbac]# 

2：创建role，编辑yaml文件如下：
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: sa-test-role
  namespace: kube-system
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "watch", "list"]   ####可以查看pod权限
- apiGroups: ["apps"]
  resources: ["deployments"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]  ##可以创建删除更新deployment等操作
  
[root@master rbac]# kubectl apply -f  role.yaml 
role.rbac.authorization.k8s.io/sa-test-role created
[root@master rbac]# 
[root@master rbac]# kubectl get role -n kube-system  | grep sa-test-role 
sa-test-role                                     2023-04-03T14:29:56Z
[root@master rbac]#

3:创建rolebind,编辑yaml文件如下
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: sa-test-rolebinding 
  namespace: kube-system
subjects:
- kind: ServiceAccount     ###绑定创建的serviceaccount账户
  name: sa-test
  namespace: kube-system
roleRef:
  kind: Role
  name: sa-test-role         ####选择使用的role
  apiGroup: rbac.authorization.k8s.io
  
[root@master rbac]# kubectl get RoleBinding -n kube-system  | grep sa-test
sa-test-rolebinding                                 Role/sa-test-role                                     23s
[root@master rbac]# 


4：创建secret，编辑yaml文件如下
apiVersion: v1
kind: Secret
metadata:
  name: secret-sa-sample
  namespace: kube-system
  annotations:
    kubernetes.io/service-account.name: "sa-test"   # 这里填写serviceAccountName
type: kubernetes.io/service-account-token

[root@master rbac]# kubectl apply -f  secret.yaml 
secret/secret-sa-test created
[root@master rbac]# kubectl get secret -nkube-system  |grep sa-test
secret-sa-test     kubernetes.io/service-account-token   3      16s
[root@master rbac]# 
#############################
注意：我使用的集群版本是 1.25.3，创建 serviceAccount 的时候发现没有生成 secret，查了一下发现从 1.24 开始就不会自动生成 secret 了。

5：获取上面创建secret token
[root@master rbac]# kubectl get secret secret-sa-test -o jsonpath={.data.token} -n kube-system |base64 -d
eyJhbGciOiJSUzI1NiIsImtpZCI6IjNBc3p2U3pSQnpLbF9jYkpYLVd4ZkR1THdMTkxGLXd4WHFDSk9ONXphWEUifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJzZWNyZXQtc2EtdGVzdCIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJzYS10ZXN0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiOWQ4OWQxZmUtN2FlYy00MTUxLWE2MzctZDE0YWMzODNkY2VjIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50Omt1YmUtc3lzdGVtOnNhLXRlc3QifQ.Ei9PdoecOuSN1Y7po7Q5ZW31OqqyLm_hRcaWtI8QK1Caf1wry_D_1ETe5tDKOnjR4Vx56jP_Fl2gNDDrj9PUb1CL_nxbKMfZLPs3chqwX6q2mYx7rJHm51K0bQcmI8iv5wRVijxZ9KmCwcRhja7mSb8yx4sfv2o4RYseQGeVE1qoEg_9FwW9dpZ9HfZPNGTYi59ABhAqNoQtVN6UQOWSeo_QHFnzGe7TPAnhtWJhFhZ_NeEGHm8jO7yAMODxLeyHnWcmAaBi0XOI0Adkh_pIrAOnQbW5dbuzO8f8KRo_lmKeeIu2nkFLK7AiDyeYpWEDSUf-0fqUNcNkyt4Jwl13-w[root@master rbac]# 
[root@master rbac]# 
[root@master rbac]#

使用获取的token登录dashboard，如下：

可以查看kube-system ns下的pod以及deployment


查看其它的资源类型没有返回结果

查看其它的ns下的资源无法查看

• 创建访问整个集群的serviceaccount账户

1: 创建sa账户，如下：
[root@master rbac]# kubectl create sa sa-admin -n kube-system 
serviceaccount/sa-admin created

2：创建clusterrole,如下：
[root@master rbac]# cat clusterrole.yaml 
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole 
metadata:
  name: sa-clusterrole
  namespace: kube-system
rules:
- apiGroups: ["*"]
  resources: ["*"]
  verbs: ["*"]
  
[root@master rbac]# 
[root@master rbac]# kubectl apply -f  clusterrole.yaml 
clusterrole.rbac.authorization.k8s.io/sa-clusterrole created
[root@master rbac]# 
[root@master rbac]# 


3： 创建clusterrolebind,如下：
[root@master rbac]# cat cluserrolebind.yaml 
kind: ClusterRoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: sa-clusterrolebinding
  namespace: kube-system
subjects:
- kind: ServiceAccount
  name: sa-admin
  namespace: kube-system
roleRef:
  kind: ClusterRole
  name: sa-clusterrole
  apiGroup: rbac.authorization.k8s.io

4：创建secret，如下；
[root@master rbac]# cat secret.yaml 
apiVersion: v1
kind: Secret
metadata:
  name: secret-sa
  namespace: kube-system
  annotations:
    kubernetes.io/service-account.name: "sa-admin"   # 这里填写serviceAccountName
type: kubernetes.io/service-account-token
[root@master rbac]# 
[root@master rbac]# kubectl apply -f  secret.yaml 
secret/secret-sa created
[root@master rbac]# 

5：获取secret的token，如下：
[root@master rbac]# kubectl get secret secret-sa -o jsonpath={.data.token} -n kube-system |base64 -d
eyJhbGciOiJSUzI1NiIsImtpZCI6IjNBc3p2U3pSQnpLbF9jYkpYLVd4ZkR1THdMTkxGLXd4WHFDSk9ONXphWEUifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJzZWNyZXQtc2EiLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC5uYW1lIjoic2EtYWRtaW4iLCJrdWJlcm5ldGVzLmlvL3NlcnZpY2VhY2NvdW50L3NlcnZpY2UtYWNjb3VudC51aWQiOiIzOGY4ZGZmYS1iZTQ3LTQxYzktOWM5Ni1kZGE3MDI4ODUzMTMiLCJzdWIiOiJzeXN0ZW06c2VydmljZWFjY291bnQ6a3ViZS1zeXN0ZW06c2EtYWRtaW4ifQ.Tzjf_v_RN59OHcRcAl6PASWUitXdVjeBRCLplZXsTbS9P56V353Tqgs3YNfRJjcEyvL9XhBwxTiKUNk9keaP-jPg32tr0iosub4w88Uvn1TUJSmUXXV1R3PbOQQslEc5l2-mShcWUYTWH9yJXP4e2DEcItyq_gIJYqzJSbFNeG96GAl8dK52-EXPgou1YebS4EmExVL2Q1AV4nazM7LgeLC0WGwwHuNxUePmBE4Goa4xOQb8eNslhqVVaJQE9wpFRni5sOr5aqJU4vQ6EhEJ6JSqfa37VZzeXDJ1n9xH2Vlwe1khTRW77yG5xtSv6mI12nLg7FiGV2XiH0X3CvLw3w[root@master rbac]# 
[root@master rbac]# 

登录k8s的dashboard界面如下：

可以查看其它ns下的资源，如下：

• 创建访问单个ns的user account

1:创建一个系统用户weizb
[root@master ~]# useradd weizb

2：使用openssl工具为用户生成私钥weizb.key
[root@master key]# openssl genrsa -out weizb.key 2048
Generating RSA private key, 2048 bit long modulus
.....................................................+++
...+++
e is 65537 (0x10001)
[root@master key]# 

3：使用上面生成的私钥，为用户生成证书请求文件weizb.csr（注意-subj后面的CN表示用户，O表示组）
[root@master key]# openssl req -new -key weizb.key -out weizb.csr -subj "/CN=weizb/O=weizb"
[root@master key]# ll
total 8
-rw-r--r-- 1 root root  907 Apr  5 19:38 weizb.csr
-rw-r--r-- 1 root root 1675 Apr  5 19:35 weizb.key
[root@master key]# 

4：使用k8s集群的CA证书，来批准证书请求，最终生成wezb.cert证书文件，有效期为500天，k8s集群证书默认在/etc/kubernetes/pki/目录下
[root@master key]# openssl x509 -req -in weizb.csr -CA /etc/kubernetes/pki/ca.crt -CAkey /etc/kubernetes/pki/ca.key -CAcreateserial -out weizb.crt -days 500
Signature ok
subject=/CN=weizb/O=weizb
Getting CA Private Key
[root@master key]# 

5：查看证书内容
[root@master key]# ll
total 12
-rw-r--r-- 1 root root  993 Apr  5 19:41 weizb.crt
-rw-r--r-- 1 root root  907 Apr  5 19:38 weizb.csr
-rw-r--r-- 1 root root 1675 Apr  5 19:35 weizb.key

[root@master key]# openssl x509 -in weizb.crt  -noout -text
Certificate:
    Data:
        Version: 1 (0x0)
        Serial Number:
            a5:2b:a2:04:18:28:79:8c
    Signature Algorithm: sha256WithRSAEncryption
        Issuer: CN=kubernetes   ###证书的颁发机构
        Validity
            Not Before: Apr  5 11:41:44 2023 GMT
            Not After : Aug 17 11:41:44 2024 GMT  ###证书有效期
        Subject: CN=weizb, O=weizb
        Subject Public Key Info:
            Public Key Algorithm: rsaEncryption
                Public-Key: (2048 bit)
                Modulus:
                    00:c5:4d:dc:b6:3b:3e:03:3b:c3:79:bc:5c:a8:31:
                    c6:7c:4c:89:6e:29:a7:60:e4:02:68:f4:4c:2f:d9:
                    d0:c3:96:9d:20:fb:7a:14:83:d7:86:0b:bd:c0:40:
                    2a:7d:4a:ab:06:75:2b:55:6d:c8:c5:fd:41:aa:ee:
                    0c:a3:1d:b9:44:fa:1a:d7:de:27:a2:c0:ff:7e:e4:
                    77:a0:ec:08:00:87:a0:8a:e6:9b:a6:9a:b7:cc:10:
                    17:10:35:05:52:0b:26:78:77:b4:75:11:0c:c2:2d:
                    e8:1b:08:8c:05:6e:74:a6:8f:16:4d:49:88:3d:1c:
                    1e:13:01:16:86:80:f4:2a:44:0c:89:52:bd:d6:d7:
                    86:3c:a1:a7:fc:f0:13:7a:18:45:85:0f:09:f0:87:
                    27:a9:5c:33:d2:22:a8:d1:c9:fd:36:21:9d:01:62:
                    b9:58:df:bc:25:95:b9:45:9d:17:94:d1:89:4e:29:
                    98:24:f5:14:f9:aa:9c:d0:71:71:93:14:bd:ef:17:
                    b1:05:8a:d9:be:a7:63:5d:88:f1:63:1e:e3:ec:18:
                    75:2a:80:e9:8e:18:23:ee:45:9b:89:65:38:82:38:
                    97:60:af:2d:e1:9d:38:ea:8e:f7:c0:f9:8f:47:f1:
                    78:96:d3:96:f4:9c:68:a6:d5:e5:1f:58:cc:18:c9:
                    da:85
                Exponent: 65537 (0x10001)
    Signature Algorithm: sha256WithRSAEncryption
         c0:b0:0e:b3:a7:59:3d:73:94:07:bb:db:6d:b3:00:38:68:a5:
         06:93:e4:ee:11:5d:b6:3b:f3:9a:c9:12:fe:38:bc:5a:6b:2a:
         1a:a3:04:8c:e0:40:51:d7:20:26:a1:48:6c:7f:39:49:3e:b7:
         cd:9a:55:99:b7:e0:4e:af:3e:80:36:c7:7b:ce:de:7a:1a:89:
         d3:da:ed:cd:2d:06:4f:92:6a:68:88:f8:87:d5:0e:16:2b:84:
         02:b2:40:a3:d1:b8:62:bc:a2:91:7f:e7:bf:8a:d7:ea:c7:b4:
         65:8d:83:58:ea:c8:39:25:e2:98:fb:27:a7:af:12:d4:a5:ff:
         99:f5:36:11:52:29:66:73:c4:ab:df:b9:66:5e:da:0e:23:6f:
         ca:3c:d9:d6:aa:d0:ec:cb:3f:84:24:94:8a:11:85:31:27:5c:
         8d:51:7d:41:61:d0:fd:32:8c:1b:41:f8:cb:3a:7f:d5:62:39:
         aa:6f:fd:33:02:0c:5d:82:77:a7:98:4d:f5:f6:c9:ea:7e:e0:
         8e:0f:67:cc:81:49:7d:27:3a:9d:61:30:a2:ff:5d:87:ae:83:
         3e:c5:a3:2a:d4:91:ba:79:18:4c:22:6d:6f:cd:5e:85:e9:3b:
         f6:8c:de:a9:e3:e1:40:71:2e:75:65:e8:a3:66:15:b2:45:09:
         c9:a7:9b:f9
[root@master key]# 


6：使用创建的证书以及私钥配置新的凭证
[root@master key]# kubectl config set-credentials weizb --client-certificate=weizb.crt --client-key=weizb.key
User "weizb" set.
[root@master key]# 

7：为用户设置上下文context，指定某一个ns
   首先确认下自己的cluster名称，如下：
[root@master key]# kubectl config get-clusters 
NAME
test.com     ###我的是test.com

[root@master key]# kubectl config set-context weizb --cluster=test.com --user=weizb --namespace=kube-system 
Context "weizb" created.
[root@master key]# 
[root@master key]#

8: 使用contex查看下是否有权限
[root@master key]# 
[root@master key]# kubectl get po --context=weizb
Error from server (Forbidden): pods is forbidden: User "weizb" cannot list resource "pods" in API group "" in the namespace "kube-system"
[root@master key]# 

9：为用户创建role
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  name: weizb-role
  namespace: kube-system
rules:
- apiGroups: [""]
  resources: ["pods"]
  verbs: ["get", "watch", "list"]
- apiGroups: ["apps"]
  resources: ["deployments"]
  verbs: ["get", "list", "watch", "create", "update", "patch", "delete"]


10：创建rolebinding，如下：
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: weizb-rolebinding
  namespace: kube-system
subjects:
- kind: User
  name: weizb
  namespace: kube-system
roleRef:
  kind: Role
  name: weizb-role
  apiGroup: rbac.authorization.k8s.io
  
11：再次查看pod,deploy资源
[root@master key]# kubectl get deploy,pod,rs,rc  --context=weizb
NAME                                      READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/calico-kube-controllers   1/1     1            1           122d
deployment.apps/coredns                   2/2     2            2           122d
deployment.apps/metrics-server            1/1     1            1           122d

NAME                                         READY   STATUS    RESTARTS        AGE
pod/calico-kube-controllers-57bcc88b-vb2q2   1/1     Running   16 (5d3h ago)   13d
pod/calico-node-4dt5p                        1/1     Running   1 (87d ago)     122d
pod/calico-node-kgmr2                        1/1     Running   1 (87d ago)     122d
pod/calico-node-pdh8x                        1/1     Running   7 (14d ago)     122d
pod/coredns-6d69f479b-2dc2f                  1/1     Running   1 (87d ago)     122d
pod/coredns-6d69f479b-m8qbn                  1/1     Running   1 (87d ago)     122d
pod/kube-apiserver-master                    1/1     Running   0               122d
pod/kube-controller-manager-master           1/1     Running   7 (2d3h ago)    122d
pod/kube-multus-ds-pjglm                     1/1     Running   0               27h
pod/kube-multus-ds-stbgf                     1/1     Running   0               27h
pod/kube-multus-ds-zxbwd                     1/1     Running   0               27h
pod/kube-proxy-ccsdp                         1/1     Running   1 (87d ago)     122d
pod/kube-proxy-tvzbc                         1/1     Running   7 (14d ago)     122d
pod/kube-proxy-x5fx5                         1/1     Running   1 (87d ago)     122d
pod/kube-scheduler-master                    1/1     Running   8 (2d3h ago)    122d
pod/metrics-server-68c648fbc7-w59hd          1/1     Running   0               20d
pod/nodelocaldns-7p9jb                       1/1     Running   1 (87d ago)     122d
pod/nodelocaldns-qzn8f                       1/1     Running   7 (14d ago)     122d
pod/nodelocaldns-tnwt6                       1/1     Running   1 (87d ago)     122d
pod/whereabouts-85tlt                        1/1     Running   0               28h
pod/whereabouts-msbf6                        1/1     Running   0               28h
pod/whereabouts-nzh89                        1/1     Running   0               28h