一.系统环境

本文主要基于Kubernetes1.21.9和Linux操作系统CentOS7.4。

Kubernetes集群架构：k8scloude1作为master节点，k8scloude2，k8scloude3作为worker节点。

二.前言

作为目前最流行的容器编排平台之一，Kubernetes提供了强大的安全性能。在Kubernetes集群中，访问控制是保障集群安全的重要组成部分。其中，身份认证是访问控制的核心。本篇博客将介绍Kubernetes中的身份认证机制。

使用身份认证的前提是已经有一套可以正常运行的Kubernetes集群，关于Kubernetes(k8s)集群的安装部署，可以查看博客《Centos7 安装部署Kubernetes(k8s)集群》https://www.cnblogs.com/renshengdezheli/p/16686769.html。

三.Kubernetes访问控制

用户使用 kubectl、客户端库或构造 REST 请求来访问 Kubernetes API。 用户账户和 Kubernetes 服务账号都可以被鉴权访问 API。 当请求到达 API 时，它会经历多个阶段，如下图所示：

整体过程简述：请求发起方进行K8s API请求，建立 TLS 后，经过Authentication（认证）、Authorization（鉴权）、AdmissionControl（准入控制）三个阶段的校验，最后把请求转化为对K8s对象的变更操作持久化至etcd中。

四.身份认证简介

Kubernetes的身份认证机制用于识别发送请求的用户是否经过身份验证。通常情况下，这个过程包括以下步骤：

1. 认证代理服务器接收到用户的请求。
2. 认证代理服务器执行对用户的身份验证。
3. 身份验证通过后，代理服务器会发出一个持有有效期的令牌，并在请求的标头中添加该令牌。
4. 进入Kubernetes API server的请求会首先检查其标头中的令牌是否存在和有效。
5. 如果令牌有效，则该请求将被允许进入API server进行处理。

用户账户：在Kubernetes中，每个用户都有一个账户，该账户用于表示用户的身份信息。账户由用户名、UID和组列表组成。其中，UID是唯一标识符，而组列表则表示用户所属的所有组。

Kubernetes支持多种身份认证方式，包括：

• 客户端证书认证
• HTTP基本认证
• Token认证
• OpenID Connect认证

五.身份认证

5.1 配置客户端机器

如下是我们的kubernetes集群。

[root@k8scloude1 ~]# kubectl get nodes -o wide
NAME         STATUS   ROLES                  AGE   VERSION   INTERNAL-IP       EXTERNAL-IP   OS-IMAGE                KERNEL-VERSION          CONTAINER-RUNTIME
k8scloude1   Ready    control-plane,master   67d   v1.21.0   192.168.110.130   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://20.10.12
k8scloude2   Ready    <none>                 67d   v1.21.0   192.168.110.129   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://20.10.12
k8scloude3   Ready    <none>                 67d   v1.21.0   192.168.110.128   <none>        CentOS Linux 7 (Core)   3.10.0-693.el7.x86_64   docker://20.10.12

先准备一台机器作为访问k8s集群的客户端，机器etcd1作为客户端，不是k8s集群的一部分。

访问k8s集群需要客户端工具kubectl，下面安装kubectl，--disableexcludes=kubernetes 表示禁掉除了这个之外的别的仓库。

[root@etcd1 ~]# yum -y install kubectl-1.21.0-0 --disableexcludes=kubernetes

配置kubectl命令自动补全。

[root@etcd1 ~]# vim /etc/profile

[root@etcd1 ~]# grep source /etc/profile
source <(kubectl completion bash)

使配置生效。

[root@etcd1 ~]# source /etc/profile

[root@etcd1 ~]# kubectl get node
The connection to the server localhost:8080 was refused - did you specify the right host or port?

5.2 使用base auth的方式进行认证

base-auth的验证方式，在kubernetes 1.19版本之后被遗弃了，所以知道有这么一种验证方式即可。

base auth验证的语法如下：kubectl -s="Kubernetes control plane地址" --username="用户名" --password="密码" get pods -n kube-system。

kubectl cluster-info可以查看集群信息，Kubernetes control plane，CoreDNS，Metrics-server地址如下。

[root@k8scloude1 ~]# kubectl cluster-info 
Kubernetes control plane is running at https://192.168.110.130:6443
CoreDNS is running at https://192.168.110.130:6443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy
Metrics-server is running at https://192.168.110.130:6443/api/v1/namespaces/kube-system/services/https:metrics-server:/proxy

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.

kubectl options命令可以列出全局使用的命令参数。

[root@k8scloude1 ~]# kubectl options
The following options can be passed to any command:

      --add-dir-header=false: If true, adds the file directory to the header of the log messages
      ......
      --password='': Password for basic authentication to the API server
      --profile='none': Name of profile to capture. One of (none|cpu|heap|goroutine|threadcreate|block|mutex)
      --profile-output='profile.pprof': Name of the file to write the profile to
      --request-timeout='0': The length of time to wait before giving up on a single server request. Non-zero values
should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests.
  -s, --server='': The address and port of the Kubernetes API server
      --skip-headers=false: If true, avoid header prefixes in the log messages
      --skip-log-headers=false: If true, avoid headers when opening log files
      --stderrthreshold=2: logs at or above this threshold go to stderr
      --tls-server-name='': Server name to use for server certificate validation. If it is not provided, the hostname
used to contact the server is used
      --token='': Bearer token for authentication to the API server
      --user='': The name of the kubeconfig user to use
      --username='': Username for basic authentication to the API server
  -v, --v=0: number for the log level verbosity
      --vmodule=: comma-separated list of pattern=N settings for file-filtered logging
      --warnings-as-errors=false: Treat warnings received from the server as errors and exit with a non-zero exit code

使用base auth的方式连接我们集群，kubernetes集群的Kubernetes control plane地址是https://192.168.110.130:6443，连接失败，因为用户qwe不存在。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --username="qwe" --password="ajkqk" get nodes
Unable to connect to the server: x509: certificate signed by unknown authority

5.3 使用token的方式进行认证

使用openssl生成一串token值。

[root@k8scloude1 ~]# openssl rand -hex 10
1b3aa30ed8b896146f0f

k8s默认不支持token认证，需要修改/etc/kubernetes/manifests/kube-apiserver.yaml 文件，启动token认证。

[root@k8scloude1 ~]# ls /etc/kubernetes/manifests/kube-apiserver.yaml 
/etc/kubernetes/manifests/kube-apiserver.yaml

启动token认证方式，添加参数 - --token-auth-file=/etc/kubernetes/pki/mytok.csv - --enable-bootstrap-token-auth=true。

[root@k8scloude1 ~]# vim /etc/kubernetes/manifests/kube-apiserver.yaml 

[root@k8scloude1 ~]# grep token-auth /etc/kubernetes/manifests/kube-apiserver.yaml
    - --token-auth-file=/etc/kubernetes/pki/mytok.csv
    - --enable-bootstrap-token-auth=true

/etc/kubernetes/pki/mytok.csv文件记录的是token，用户信息。/etc/kubernetes/pki/mytok.csv文件格式：token,用户名,id。

1b3aa30ed8b896146f0f,test,3表示test用户的id为3，token值为1b3aa30ed8b896146f0f。

[root@k8scloude1 ~]# vim /etc/kubernetes/pki/mytok.csv

[root@k8scloude1 ~]# cat /etc/kubernetes/pki/mytok.csv
1b3aa30ed8b896146f0f,test,3

重启kubelet使kube-apiserver.yaml 配置生效。

[root@k8scloude1 ~]# systemctl restart kubelet

[root@k8scloude1 ~]# systemctl status kubelet
● kubelet.service - kubelet: The Kubernetes Node Agent
   Loaded: loaded (/usr/lib/systemd/system/kubelet.service; enabled; vendor preset: disabled)
  Drop-In: /usr/lib/systemd/system/kubelet.service.d
           └─10-kubeadm.conf
   Active: active (running) since 五 2022-03-18 01:52:33 CST; 1s ago
     Docs: https://kubernetes.io/docs/
 Main PID: 91790 (kubelet)
   Memory: 50.2M
   CGroup: /system.slice/kubelet.service
           └─91790 /usr/bin/kubelet --bootstrap-kubeconfig=/etc/kubernetes/bootstrap-kubelet.conf --kubeconfig=/etc/kubernetes/kubelet.conf --config=/var/lib/kubelet/config.yaml --network-plugin=cni --pod-in...

下面在客户端使用token进行认证，token值为/etc/kubernetes/pki/mytok.csv里的token值。报证书问题的错误。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --token='1b3aa30ed8b896146f0f' get nodes
Unable to connect to the server: x509: certificate signed by unknown authority

--insecure-skip-tls-verify=true 忽略证书认证。可以看到认证成功，get nodes查看集群节点，但是没有权限查看集群节点，关于授权下一篇博客会讲。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --token='1b3aa30ed8b896146f0f' --insecure-skip-tls-verify=true get nodes
Error from server (Forbidden): nodes is forbidden: User "test" cannot list resource "nodes" in API group "" at the cluster scope

查看pod。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --token='1b3aa30ed8b896146f0f' --insecure-skip-tls-verify=true get pod
Error from server (Forbidden): pods is forbidden: User "test" cannot list resource "pods" in API group "" in the namespace "default"

查看kube-system命名空间下的pod，可以发现用户test使用token认证通过了，但是没有资源的访问权限，进行资源的授权即可 。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --token='1b3aa30ed8b896146f0f' --insecure-skip-tls-verify=true get pod -n kube-system
Error from server (Forbidden): pods is forbidden: User "test" cannot list resource "pods" in API group "" in the namespace "kube-system"

使用错误的token就认证失败Unauthorized。

[root@etcd1 ~]# kubectl -s="https://192.168.110.130:6443" --token='1b3aa30ed8b896146f0g' --insecure-skip-tls-verify=true get pod -n kube-system
error: You must be logged in to the server (Unauthorized)

5.4 使用管理员的kubeconfig文件进行认证

kubeconfig文件不是一个名字叫做kubeconfig的文件，而是用于做认证的文件我们就叫做kubeconfig文件，如果qwe.txt里有认证信息，则qwe.txt也就是kubeconfig文件。

安装好kubernetes集群之后，系统会生成一个管理员权限的kubeconfig文件：/etc/kubernetes/admin.conf。

[root@k8scloude1 ~]# ls /etc/kubernetes/
admin.conf  controller-manager.conf  kubelet.conf  manifests  pki  scheduler.conf

[root@k8scloude1 ~]# ls /etc/kubernetes/admin.conf 
/etc/kubernetes/admin.conf

切换到tom用户。

[root@k8scloude1 ~]# su - tom

因为Tom用户没有kubeconfig文件，所以连接不上k8s。

[tom@k8scloude1 ~]$ kubectl get nodes
The connection to the server localhost:8080 was refused - did you specify the right host or port?

[tom@k8scloude1 ~]$ exit
登出

root用户的家目录下有kubeconfig文件，所以可以连接k8s。

[root@k8scloude1 ~]# kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   67d   v1.21.0
k8scloude2   Ready    <none>                 67d   v1.21.0
k8scloude3   Ready    <none>                 67d   v1.21.0

tom用户不能查看k8s节点状态，原因为没有kubeconfig文件。用户默认使用的kubeconfig文件是 ~/.kube/config ,比如：/root/.kube/config。

把具有管理员权限的kubeconfig文件：admin.conf复制到tom用户家目录下面。

[root@k8scloude1 ~]# cp /etc/kubernetes/admin.conf /home/tom/

修改属主。

[root@k8scloude1 ~]# chown tom:tom /home/tom/admin.conf 

切换到tom用户。

[root@k8scloude1 ~]# su - tom
上一次登录：五 3月 18 11:48:02 CST 2022pts/0 上

[tom@k8scloude1 ~]$ ls
admin.conf

[tom@k8scloude1 ~]$ ll -h
总用量 8.0K
-rw------- 1 tom tom 5.5K 3月  18 11:55 admin.conf

查看k8s节点状态，--kubeconfig 指定所使用的kubeconfig文件。

[tom@k8scloude1 ~]$ kubectl --kubeconfig=admin.conf get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   67d   v1.21.0
k8scloude2   Ready    <none>                 67d   v1.21.0
k8scloude3   Ready    <none>                 67d   v1.21.0

也可以设置环境变量。

[tom@k8scloude1 ~]$ export KUBECONFIG=admin.conf

[tom@k8scloude1 ~]$ kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   67d   v1.21.0
k8scloude2   Ready    <none>                 67d   v1.21.0
k8scloude3   Ready    <none>                 67d   v1.21.0

取消环境变量。

[tom@k8scloude1 ~]$ unset KUBECONFIG

[tom@k8scloude1 ~]$ kubectl get nodes
The connection to the server localhost:8080 was refused - did you specify the right host or port?

把admin.conf复制到家目录下的隐藏文件里。

[tom@k8scloude1 ~]$ ls ~/.kube/
cache

[tom@k8scloude1 ~]$ cp admin.conf ~/.kube/config

[tom@k8scloude1 ~]$ kubectl get nodes
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   67d   v1.21.0
k8scloude2   Ready    <none>                 67d   v1.21.0
k8scloude3   Ready    <none>                 67d   v1.21.0

要让其他客户端可以使用kubectl管理k8s，把kubeconfig文件拷贝到相应客户端机器即可。

[tom@k8scloude1 ~]$ scp admin.conf root@192.168.110.133:

在客户端使用kubeconfig文件连接k8s。

[root@etcd1 ~]# ls
admin.conf  

[root@etcd1 ~]# kubectl --kubeconfig=admin.conf get node
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   67d   v1.21.0
k8scloude2   Ready    <none>                 67d   v1.21.0
k8scloude3   Ready    <none>                 67d   v1.21.0

5.5 使用自定义的kubeconfig文件进行认证

/etc/kubernetes/admin.conf这个认证文件具有管理员权限，不适合普通用户使用，具有安全风险，接下来我们给普通用户创建一个自定义的kubeconfig文件。

kubectl config view获取kubeconfig文件结构，关于kubeconfig文件的详细介绍，请查看博客《k8s多集群切换：使用kubeconfig文件管理多套kubernetes(k8s)集群》。

[tom@k8scloude1 ~]$ kubectl config view 
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: DATA+OMITTED
    server: https://192.168.110.130:6443
  name: kubernetes
contexts:
- context:
    cluster: kubernetes
    user: kubernetes-admin
  name: kubernetes-admin@kubernetes
current-context: kubernetes-admin@kubernetes
kind: Config
preferences: {}
users:
- name: kubernetes-admin
  user:
    client-certificate-data: REDACTED
    client-key-data: REDACTED

创建目录存放相关文件。

[root@k8scloude1 ~]# mkdir safe

[root@k8scloude1 ~]# cd safe/

创建命名空间。

[root@k8scloude1 safe]# kubectl create ns safe
namespace/safe created

切换namespace。

[root@k8scloude1 safe]# kubens safe
Context "kubernetes-admin@kubernetes" modified.
Active namespace is "safe".

[root@k8scloude1 safe]# kubectl get pod 
No resources found in safe namespace.

5.5.1 申请证书

下面开始申请证书。

创建私钥，名字可以自己命名为 test.key。

[root@k8scloude1 safe]# openssl genrsa -out test.key 2048
Generating RSA private key, 2048 bit long modulus
...............................+++
.....................................................................................+++
e is 65537 (0x10001)

利用刚生成的私钥test.key ，生成证书请求文件 test.csr，CN 的值 test，就是我们授权的用户。

[root@k8scloude1 safe]# openssl req -new -key test.key -out test.csr -subj "/CN=test/O=cka2020"

[root@k8scloude1 safe]# ls
test.csr  test.key

对证书请求文件test.csr进行 base64 编码。

[root@k8scloude1 safe]# cat test.csr | base64 | tr -d "\n"
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[root@k8scloude1 safe]# 

编写申请证书请求文件的 yaml 文件，注意：这里 apiVersion 要带 beta1，否则 signerName 那行就不能注释掉，但这样的话后面的 操作就不能获取到证书。这里 request 里的是 base64 编码之后的证书请求文件。

[root@k8scloude1 safe]# vim csr.yaml

[root@k8scloude1 safe]# cat csr.yaml 
apiVersion: certificates.k8s.io/v1beta1
kind: CertificateSigningRequest
metadata:
  name: test
spec:
  groups:
  - system:authenticated
  #signerName: kubernetes.io/legacy-aa #注意这行是被注释掉的
  request: 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
  usages:
  - client auth

申请证书。

[root@k8scloude1 safe]# kubectl apply -f csr.yaml 
Warning: certificates.k8s.io/v1beta1 CertificateSigningRequest is deprecated in v1.19+, unavailable in v1.22+; use certificates.k8s.io/v1 CertificateSigningRequest
certificatesigningrequest.certificates.k8s.io/test created

查看已经发出证书申请的请求。

[root@k8scloude1 safe]# kubectl get csr -o wide
NAME   AGE   SIGNERNAME                     REQUESTOR          CONDITION
test   95s   kubernetes.io/legacy-unknown   kubernetes-admin   Pending

批准证书。

[root@k8scloude1 safe]# kubectl certificate approve test
certificatesigningrequest.certificates.k8s.io/test approved

查看审批通过的证书。

[root@k8scloude1 safe]# kubectl get csr -o wide
NAME   AGE     SIGNERNAME                     REQUESTOR          CONDITION
test   3m15s   kubernetes.io/legacy-unknown   kubernetes-admin   Approved,Issued

以yaml文件的格式查看审批通过的证书。

[root@k8scloude1 safe]# kubectl get csr test -o yaml
apiVersion: certificates.k8s.io/v1
kind: CertificateSigningRequest
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"certificates.k8s.io/v1beta1","kind":"CertificateSigningRequest","metadata":{"annotations":{},"name":"test"},"spec":{"groups":["system:authenticated"],"request":"......","usages":["client auth"]}}
  creationTimestamp: "2022-03-18T07:46:23Z"
  name: test
  resourceVersion: "2771685"
  selfLink: /apis/certificates.k8s.io/v1/certificatesigningrequests/test
  uid: b04adc21-54c9-4fc7-b2bd-5544b74ee647
spec:
  groups:
  - system:masters
  - system:authenticated
  request: ......
  signerName: kubernetes.io/legacy-unknown
  usages:
  - client auth
  username: kubernetes-admin
status:
  certificate: ......
  conditions:
  - lastTransitionTime: "2022-03-18T07:49:32Z"
    lastUpdateTime: "2022-03-18T07:49:32Z"
    message: This CSR was approved by kubectl certificate approve.
    reason: KubectlApprove
    status: "True"
    type: Approved

/etc/kubernetes/pki/目录下存放的都是集群的证书。

[root@k8scloude1 safe]# ls /etc/kubernetes/pki/
apiserver.crt              apiserver-etcd-client.key  apiserver-kubelet-client.crt  ca.crt  etcd                front-proxy-ca.key      front-proxy-client.key  sa.key
apiserver-etcd-client.crt  apiserver.key              apiserver-kubelet-client.key  ca.key  front-proxy-ca.crt  front-proxy-client.crt  mytok.csv               sa.pub

只查看certificate字段，查看证书。

[root@k8scloude1 safe]# kubectl get csr/test -o jsonpath='{.status.certificate}'
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[root@k8scloude1 safe]# 

对certificate解码并导出证书文件。

[root@k8scloude1 safe]# kubectl get csr/test -o jsonpath='{.status.certificate}' | base64 -d > test.crt

查看证书文件。

[root@k8scloude1 safe]# ls
csr.yaml  test.crt  test.csr  test.key

[root@k8scloude1 safe]# cat test.crt 
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----

[root@k8scloude1 safe]# ls
csr.yaml  test.crt  test.csr  test.key

test用户的证书文件就申请好了。

5.5.2 生成test用户的kubeconfig文件

拷贝 CA 证书。

[root@k8scloude1 safe]# cp /etc/kubernetes/pki/ca.crt .

[root@k8scloude1 safe]# ls
ca.crt  csr.yaml  test.crt  test.csr  test.key

kubeconfig文件包含3个字段：cluster,user,context上下文(可以把cluster和user关联在一起)，kubeconfig文件里，clusters 字段指定 kubernetes 集群的信息，users 指定用户，contexts 用于 指定上下文，包括用户默认所在的命名空间等信息。

设置集群字段：--kubeconfig指定生成的kubeconfig文件名，set-cluster指定集群名，--server指定连接的那个k8s上，--certificate-authority 指定CA证书，--embed-certs=true 的意思是把CA证书内容写入到此 kubeconfig 文件里。

[root@k8scloude1 safe]# kubectl config --kubeconfig=kctest set-cluster clustertest --server=https://192.168.110.130:6443 --certificate-authority=ca.crt --embed-certs=true
Cluster "clustertest" set.

查看kctest 。

[root@k8scloude1 safe]# ls
ca.crt  csr.yaml  kctest  test.crt  test.csr  test.key

[root@k8scloude1 safe]# cat kctest 
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://192.168.110.130:6443
  name: clustertest
contexts: null
current-context: ""
kind: Config
preferences: {}
users: null

这里--embed-certs=true 的意思是把CA证书内容写入到此 kubeconfig 文件里，如果--embed-certs=false，使用kctest文件还要把ca.crt也要拷贝到相应地方。

[root@k8scloude1 safe]# kubectl config --kubeconfig=kctest set-cluster clustertest --server=https://192.168.110.130:6443 --certificate-authority=ca.crt --embed-certs=false
Cluster "clustertest" set.

[root@k8scloude1 safe]# cat kctest 
apiVersion: v1
clusters:
- cluster:
    certificate-authority: ca.crt
    server: https://192.168.110.130:6443
  name: clustertest
contexts: null
current-context: ""
kind: Config
preferences: {}
users: null

设置集群字段。

[root@k8scloude1 safe]# kubectl config --kubeconfig=kctest set-cluster clustertest --server=https://192.168.110.130:6443 --certificate-authority=ca.crt --embed-certs=true
Cluster "clustertest" set.

设置用户字段。

[root@k8scloude1 safe]# kubectl config --kubeconfig=kctest set-credentials test --client-certificate=test.crt --client-key=test.key --embed-certs=true
User "test" set.

查看kctest 。

[root@k8scloude1 safe]# cat kctest 
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://192.168.110.130:6443
  name: clustertest
contexts: null
current-context: ""
kind: Config
preferences: {}
users:
- name: test
  user:
    client-certificate-data: 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
    client-key-data: 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

设置上下文字段。

[root@k8scloude1 safe]# kubectl config --kubeconfig=kctest set-context contexttest --cluster=clustertest --namespace=default --user=test
Context "contexttest" created.

现在kctest就是一个完整的kubeconfig文件了。

[root@k8scloude1 safe]# cat kctest 
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://192.168.110.130:6443
  name: clustertest
contexts:
- context:
    cluster: clustertest
    namespace: default
    user: test
  name: contexttest
current-context: ""
kind: Config
preferences: {}
users:
- name: test
  user:
    client-certificate-data: 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
    client-key-data: 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

修改kctest，修改当前上下文为contexttest：current-context: "contexttest"。

[root@k8scloude1 safe]# vim kctest 

[root@k8scloude1 safe]# cat kctest 
apiVersion: v1
clusters:
- cluster:
    certificate-authority-data: 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
    server: https://192.168.110.130:6443
  name: clustertest
contexts:
- context:
    cluster: clustertest
    namespace: default
    user: test
  name: contexttest
current-context: "contexttest"
kind: Config
preferences: {}
users:
- name: test
  user:
    client-certificate-data: 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
    client-key-data: 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

5.5.3 使用test用户的kubeconfig文件进行认证

只要客户端机器使用kctest文件，用户test就可以连接集群clustertest了。

把kctest文件拷贝到客户端机器。

[root@k8scloude1 safe]# scp kctest 192.168.110.133:~

[root@etcd1 ~]# ls kctest 
kctest

--kubeconfig指定使用的kubeconfig文件，发现用户test认证成功了，但是没有权限。

[root@etcd1 ~]# kubectl get nodes --kubeconfig=kctest 
Error from server (Forbidden): nodes is forbidden: User "test" cannot list resource "nodes" in API group "" at the cluster scope

对test用户授予cluster-admin的权限，对test用户进行授权，kctest里存储的是test用户的证书和私钥，所以kctest就具备了test的权限。

[root@k8scloude1 safe]# kubectl create clusterrolebinding test --clusterrole=cluster-admin --user=test
clusterrolebinding.rbac.authorization.k8s.io/test created

对test用户授予cluster-admin的权限之后，客户端可以查看节点信息了。

[root@etcd1 ~]# kubectl get nodes --kubeconfig=kctest 
NAME         STATUS   ROLES                  AGE   VERSION
k8scloude1   Ready    control-plane,master   68d   v1.21.0
k8scloude2   Ready    <none>                 68d   v1.21.0
k8scloude3   Ready    <none>                 68d   v1.21.0

取消用户test的授权。

[root@k8scloude1 safe]# kubectl delete clusterrolebinding test
clusterrolebinding.rbac.authorization.k8s.io "test" deleted

取消用户test的授权之后，用户test只能认证成功，但是没有权限。

[root@etcd1 ~]# kubectl get nodes --kubeconfig=kctest 
Error from server (Forbidden): nodes is forbidden: User "test" cannot list resource "nodes" in API group "" at the cluster scope

可以查看所有的集群角色绑定。

[root@k8scloude1 safe]# kubectl get clusterrolebinding
NAME                                                   ROLE                                                                               AGE
calico-kube-controllers                                ClusterRole/calico-kube-controllers                                                68d
calico-node                                            ClusterRole/calico-node                                                            68d
cluster-admin                                          ClusterRole/cluster-admin                                                          68d
ingress-nginx                                          ClusterRole/ingress-nginx                                                          31d
ingress-nginx-admission                                ClusterRole/ingress-nginx-admission                                                31d
kubeadm:get-nodes                                      ClusterRole/kubeadm:get-nodes                                                      68d
kubeadm:kubelet-bootstrap                              ClusterRole/system:node-bootstrapper                                               68d
......
system:controller:endpointslice-controller             ClusterRole/system:controller:endpointslice-controller                             68d
system:controller:endpointslicemirroring-controller    ClusterRole/system:controller:endpointslicemirroring-controller                    68d
system:controller:ephemeral-volume-controller          ClusterRole/system:controller:ephemeral-volume-controller                          68d

system:service-account-issuer-discovery                ClusterRole/system:service-account-issuer-discovery                                68d
system:volume-scheduler                                ClusterRole/system:volume-scheduler                                                68d

验证test用户是否具有list当前命名空间里的 pod 的权限。

[root@k8scloude1 ~]# kubectl auth can-i list pods --as test
yes

验证test用户是否具有list命名空间kube-system里pod的权限。

[root@k8scloude1 ~]# kubectl auth can-i list pods -n kube-system --as test
yes

六.总结

本文介绍了Kubernetes(k8s)访问控制之一的用户认证。并重点介绍了base auth认证，token认证，kubeconfig认证。提供了相关代码示例。通过本文的介绍，读者可以更好地理解Kubernetes的访问控制机制，并学会如何在Kubernetes中实现用户认证。