通过curl访问k8s集群获取证书或token的方式

K8S安全控制框架主要由下面3个阶段进行控制，每一个阶段都支持插件方式，通过API Server配置来启用插件。
1. Authentication（认证）
2. Authorization（授权）
3. Admission Control（准入控制）

客户端（kubectl或curl等）要想访问K8s集群API Server，一般需要证书、Token或者用户名+密码。如果Pod访问，需要ServiceAccount。
认证（Authentication）
三种客户端身份认证：
HTTPS 证书认证：基于CA证书签名的数字证书认证
HTTP Token认证：通过一个Token来识别用户
HTTP Base认证：用户名+密码的方式认证

鉴权（Authentication）
RBAC（Role-Based Access Control，基于角色的访问控制）：负责完成授权（Authorization）工作。 RBAC根据API请求属性，决定允许还是拒绝。
比较常见的授权维度：
• user：用户名
• group：用户分组
• 资源，例如pod、deployment
• 资源操作方法：get，list，create，update，patch，watch，delete
• 命名空间
• API组

基于角色的权限访问控制：RBAC
RBAC（Role-Based Access Control，基于角色的访问控制），允许通过Kubernetes API动态配置策略。
角色
• Role：授权特定命名空间的访问权限
• ClusterRole：授权所有命名空间的访问权限
角色绑定
• RoleBinding：将角色绑定到主体（即subject）
• ClusterRoleBinding：将集群角色绑定到主体
主体（subject）
• User：用户
• Group：用户组
• ServiceAccount：服务账号

Kubernetes RBAC 为指定用户授权访问不同命名空间权限_k8s dashbord 用户授权-CSDN博客

第一种：客户端访问

证书

1）ca根证书

[root@k8s-node02 ~]# grep certificate-auth ~/.kube/config  | cut -d " " -f 6 |base64 -d>ca.pem

2）client-cert

[root@k8s-node02 ~]# grep client-cert ~/.kube/config  | cut -d " " -f 6 | base64 -d>client-cert.cert

3）client-key

[root@k8s-node02 ~]# grep client-key-data ~/.kube/config  | cut -d " " -f 6 |base64 -d>client-key.key

4）然后访问集群：

[root@k8s-node02 ~]# curl -k  --cert ./client-cert.cert --key ./client-key.key   https://rancher.jettech.cn

5）访问某个节点的监控接口：

[root@k8s-node02 ~]# netstat -atunpl |grep kubelet
tcp        0      0 127.0.0.1:10248         0.0.0.0:*               LISTEN      4014/kubelet        
tcp        0      0 127.0.0.1:42873         0.0.0.0:*               LISTEN      4014/kubelet        
tcp        0      0 127.0.0.1:36198         127.0.0.1:6443          ESTABLISHED 4014/kubelet        
tcp        0      0 127.0.0.1:36179         127.0.0.1:6443          ESTABLISHED 4014/kubelet        
tcp        0      0 127.0.0.1:36206         127.0.0.1:6443          ESTABLISHED 4014/kubelet        
tcp        0      0 127.0.0.1:36202         127.0.0.1:6443          ESTABLISHED 4014/kubelet        
tcp        0      0 127.0.0.1:36204         127.0.0.1:6443          ESTABLISHED 4014/kubelet        
tcp6       0      0 :::10250                :::*                    LISTEN      4014/kubelet        
tcp6       0      0 172.16.10.59:10250      10.42.14.65:56272       ESTABLISHED 4014/kubelet        
[root@k8s-node02 ~]# curl -k  --cert ./client-cert.cert --key ./client-key.key   https://localhost:10250/metrics

第二种：pod访问

创建k8s的用户，用户分为普通用户和serviceAccount用户

useraccount：外部用户

serviceAccount：内部集群资源直接访问的用户

1.serviceAccount用户的创建：

1.1）创建一个namespace

[root@k8s-node02 ~]# kubectl create namespace wubo

1.2）创建serviceaccount 会自动创建一个secret资源

apiVersion: v1
kind: ServiceAccount
metadata:
  name: wubo-service-account
  namespace: wubo

查看serviceaccount

[root@k8s-node02 ~]# kubectl get sa -n wubo wubo-service-account -o yaml
apiVersion: v1
kind: ServiceAccount
metadata:
  creationTimestamp: "2024-01-22T04:35:54Z"
  name: wubo-service-account
  namespace: wubo
  resourceVersion: "14544"
  uid: 3db644bc-2f2a-4183-a0f2-c8178d288bde
secrets:
- name: wubo-service-account-token-2vxk4

查看secret

[root@k8s-node02 ~]# kubectl get secrets -n wubo wubo-service-account-token-2vxk4 -o yaml
apiVersion: v1
data:
  ca.crt: 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
  namespace: d3Vibw==
  token: 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
kind: Secret
metadata:
  annotations:
    kubernetes.io/service-account.name: wubo-service-account
    kubernetes.io/service-account.uid: 3db644bc-2f2a-4183-a0f2-c8178d288bde
  creationTimestamp: "2024-01-22T04:35:54Z"
  managedFields:
  - apiVersion: v1
    fieldsType: FieldsV1
    fieldsV1:
      f:data:
        .: {}
        f:ca.crt: {}
        f:namespace: {}
        f:token: {}
      f:metadata:
        f:annotations:
          .: {}
          f:kubernetes.io/service-account.name: {}
          f:kubernetes.io/service-account.uid: {}
      f:type: {}
    manager: kube-controller-manager
    operation: Update
    time: "2024-01-22T04:35:54Z"
  name: wubo-service-account-token-2vxk4
  namespace: wubo
  resourceVersion: "14543"
  uid: 70ae3e2a-1b91-498d-9bc8-56c8522d42b1
type: kubernetes.io/service-account-token

此时就可以获取token了和ca.crt

[root@k8s-node02 ~]# kubectl get secret  -n wubo wubo-service-account-token-2vxk4 -o jsonpath={.data.token} | base64 -d

namespace：

[root@k8s-node02 ~]# kubectl get secret  -n wubo wubo-service-account-token-2vxk4 -o jsonpath={.data.namespace} |base64  -d

ca.crt

[root@k8s-node02 ~]# kubectl get secret  -n wubo wubo-service-account-token-2vxk4 -o jsonpath={.data.ca\\.crt} |base64  -d

1.3)创建全局的资源权限ClusterRole是全局的，不分namespace

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: wubo-cluster-role
rules:
- apiGroups:
  - ""
  resources:
  - '*'
  #- ["pods","pods/log","pods/exec", "pods/attach", "pods/status","services","nodes/metrics","nodes/stats","nodes/proxy",]
  verbs:
  #- ["get", "watch", "list", "create", "update", "patch", "delete","exec"]
  - '*'

1.4）创建绑定用户和集群角色绑定

---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: wubo-cluster-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: wubo-cluster-role
subjects:
- kind: ServiceAccount
  name: wubo-service-account
  namespace: wubo

all文件：

[root@k8s-node02 ~]# cat auth.yaml 
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  name: wubo-cluster-role
rules:
- apiGroups:
  - ""
  resources:
  - '*'
  #- ["pods","pods/log","pods/exec", "pods/attach", "pods/status","services","nodes/metrics","nodes/stats","nodes/proxy",]
  verbs:
  #- ["get", "watch", "list", "create", "update", "patch", "delete","exec"]
  - '*'
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: wubo-service-account
  namespace: wubo
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: wubo-cluster-role-binding
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: wubo-cluster-role
subjects:
- kind: ServiceAccount
  name: wubo-service-account
  namespace: wubo