Kubernetes K8S之存储Secret详解

男娘i 2022-12-27 08:35 443阅读 0赞

### Kubernetes K8S之存储Secret详解 ###

*  Secret概述
 *   *  Secret类型
 *  Service Account
 *  Opaque Secret
 *   *  创建secret
     *  将Secret挂载到Volume中
     *  将Secret导入到环境变量中
 *  docker-registry Secret
 *   *  harbor镜像仓库
     *  pod直接下载镜像
     *  pod通过Secret下载镜像

原文地址：  
[Kubernetes K8S之存储Secret详解][Kubernetes K8S_Secret]

# Secret概述 #

Secret解决了密码、token、秘钥等敏感数据的配置问题，而不需要把这些敏感数据暴露到镜像或者Pod Spec中。Secret可以以Volume或者环境变量的方式使用。

用户可以创建 secret，同时系统也创建了一些 secret。

要使用 secret，pod 需要引用 secret。Pod 可以用两种方式使用 secret：作为 volume 中的文件被挂载到 pod 中的一个或者多个容器里，或者当 kubelet 为 pod 拉取镜像时使用。

## Secret类型 ##

*  Service Account：用来访问Kubernetes API，由Kubernetes自动创建，并且会自动挂载到Pod的 /run/secrets/kubernetes.io/serviceaccount 目录中。
 *  Opaque：base64编码格式的Secret，用来存储密码、秘钥等。
 *  kubernetes.io/dockerconfigjson：用来存储私有docker registry的认证信息。

# Service Account #

通过kube-proxy查看

[root@k8s-master ~]# kubectl get pod -A | grep 'kube-proxy'
    kube-system            kube-proxy-6bfh7                             1/1     Running   12         7d3h
    kube-system            kube-proxy-6vfkf                             1/1     Running   11         7d3h
    kube-system            kube-proxy-bvl9n                             1/1     Running   11         7d3h
    [root@k8s-master ~]#
    [root@k8s-master ~]# kubectl exec -it -n kube-system kube-proxy-6bfh7 -- /bin/sh
    # ls -l /run/secrets/kubernetes.io/serviceaccount
    total 0
    lrwxrwxrwx 1 root root 13 Jun  8 13:39 ca.crt -> ..data/ca.crt
    lrwxrwxrwx 1 root root 16 Jun  8 13:39 namespace -> ..data/namespace
    lrwxrwxrwx 1 root root 12 Jun  8 13:39 token -> ..data/token

# Opaque Secret #

## 创建secret ##

手动加密，基于base64加密

[root@k8s-master ~]# echo -n 'admin' | base64
    YWRtaW4=
    [root@k8s-master ~]# echo -n '1f2d1e2e67df' | base64
    MWYyZDFlMmU2N2Rm

yaml文件

1 [root@k8s-master secret]# pwd
     2 /root/k8s_practice/secret
     3 [root@k8s-master secret]# cat secret.yaml 
     4 apiVersion: v1
     5 kind: Secret
     6 metadata:
     7   name: mysecret
     8 type: Opaque
     9 data:
    10   username: YWRtaW4=
    11   password: MWYyZDFlMmU2N2Rm

或者通过如下命令行创建【secret名称故意设置不一样，以方便查看对比】，生成secret后会自动加密，而非明文存储。

kubectl create secret generic db-user-pass --from-literal=username=admin --from-literal=password=1f2d1e2e67df

生成secret，并查看状态

[root@k8s-master secret]# kubectl apply -f secret.yaml
    secret/mysecret created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get secret   ### 查看默认名称空间的secret简要信息
    NAME                  TYPE                                  DATA   AGE
    basic-auth            Opaque                                1      2d12h
    default-token-v48g4   kubernetes.io/service-account-token   3      27d
    mysecret              Opaque                                2      23s  ### 可见已创建
    tls-secret            kubernetes.io/tls                     2      3d2h
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get secret mysecret -o yaml     ### 查看mysecret详细信息
    apiVersion: v1
    data:
      password: MWYyZDFlMmU2N2Rm
      username: YWRtaW4=
    kind: Secret
    metadata:
      annotations:
        kubectl.kubernetes.io/last-applied-configuration: |
          {"apiVersion":"v1","data":{"password":"MWYyZDFlMmU2N2Rm","username":"YWRtaW4="},"kind":"Secret","metadata":{"annotations":{},"name":"mysecret","namespace":"default"},"type":"Opaque"}
      creationTimestamp: "2020-06-08T14:08:59Z"
      name: mysecret
      namespace: default
      resourceVersion: "987419"
      selfLink: /api/v1/namespaces/default/secrets/mysecret
      uid: 27b58929-71c4-495b-99a5-0d411910a529
    type: Opaque
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl describe secret mysecret     ### 查看描述信息
    Name:         mysecret
    Namespace:    default
    Labels:       <none>
    Annotations:
    Type:         Opaque
    
    Data
    ====
    password:  12 bytes
    username:  5 bytes

## 将Secret挂载到Volume中 ##

yaml文件

[root@k8s-master secret]# pwd
    /root/k8s_practice/secret
    [root@k8s-master secret]# cat pod_secret_volume.yaml
    apiVersion: v1
    kind: Pod
    metadata:
      name: pod-secret-volume
    spec:
      containers:
      - name: myapp
        image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1
        volumeMounts:
        - name: secret-volume
          mountPath: /etc/secret
          readOnly: true
      volumes:
      - name: secret-volume
        secret:
          secretName: mysecret

启动pod并查看状态

[root@k8s-master secret]# kubectl apply -f pod_secret_volume.yaml
    pod/pod-secret-volume created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get pod -o wide
    NAME                READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
    pod-secret-volume   1/1     Running   0          16s   10.244.2.159   k8s-node02   <none>           <none>

查看secret信息

[root@k8s-master secret]# kubectl exec -it pod-secret-volume -- /bin/sh
    / # ls /etc/secret
    password  username
    / #
    / # cat /etc/secret/username
    admin/ #
    / #
    / # cat /etc/secret/password
    1f2d1e2e67df/ #

由上可见，在pod中的secret信息实际已经被解密。

## 将Secret导入到环境变量中 ##

yaml文件

[root@k8s-master secret]# pwd
    /root/k8s_practice/secret
    [root@k8s-master secret]# cat pod_secret_env.yaml
    apiVersion: v1
    kind: Pod
    metadata:
      name: pod-secret-env
    spec:
      containers:
      - name: myapp
        image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1
        env:
        - name: SECRET_USERNAME
          valueFrom:
            secretKeyRef:
              name: mysecret
              key: username
        - name: SECRET_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysecret
              key: password
      restartPolicy: Never

启动pod并查看状态

[root@k8s-master secret]# kubectl apply -f pod_secret_env.yaml
    pod/pod-secret-env created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get pod -o wide
    NAME             READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
    pod-secret-env   1/1     Running   0          6s    10.244.2.160   k8s-node02   <none>           <none>

查看secret信息

[root@k8s-master secret]# kubectl exec -it pod-secret-env -- /bin/sh
    / # env
    ………………
    HOME=/root
    SECRET_PASSWORD=1f2d1e2e67df    ### secret信息
    MYAPP_SVC_PORT_80_TCP=tcp://10.98.57.156:80
    TERM=xterm
    NGINX_VERSION=1.12.2
    KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1
    PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
    KUBERNETES_PORT_443_TCP_PORT=443
    KUBERNETES_PORT_443_TCP_PROTO=tcp
    MYAPP_SVC_SERVICE_HOST=10.98.57.156
    SECRET_USERNAME=admin    ### secret信息
    KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443
    ………………

由上可见，在pod中的secret信息实际已经被解密。

# docker-registry Secret #

## harbor镜像仓库 ##

首先使用harbor搭建镜像仓库，搭建部署过程参考：「[Harbor企业级私有Docker镜像仓库部署][Harbor_Docker]」

**harbor部分配置文件信息**

[root@k8s-master harbor]# pwd
    /root/App/harbor
    [root@k8s-master harbor]# vim harbor.yml
    # Configuration file of Harbor
    hostname: 172.16.1.110
    
    # http related config
    http:
      # port for http, default is 80. If https enabled, this port will redirect to https port
      port: 5000
    
    # https related config
    https:
      # https port for harbor, default is 443
      port: 443
      # The path of cert and key files for nginx
      certificate: /etc/harbor/cert/httpd.crt
      private_key: /etc/harbor/cert/httpd.key
    harbor_admin_password: Harbor12345

**启动harbor后客户端http设置**

集群所有机器都要操作

[root@k8s-master ~]# vim /etc/docker/daemon.json
    {
      "exec-opts": ["native.cgroupdriver=systemd"],
      "log-driver": "json-file",
      "log-opts": {
        "max-size": "100m"
      },
      "insecure-registries": ["172.16.1.110:5000"]
    }
    [root@k8s-master ~]#
    [root@k8s-master ~]# systemctl restart docker   # 重启docker服务

添加了 “insecure-registries”: \[“172.16.1.110:5000”\] 这行，其中172.16.1.110为内网IP地址。该文件必须符合 json 规范，否则 Docker 将不能启动。

如果在Harbor所在的机器重启了docker服务，记得要重新启动Harbor。

**创建「私有」仓库**

**![img][]**

**镜像上传**

docker pull registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1
    docker tag registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 172.16.1.110:5000/k8s-secret/myapp:v1
    # 登录
    docker login 172.16.1.110:5000 -u admin -p Harbor12345
    # 上传
    docker push 172.16.1.110:5000/k8s-secret/myapp:v1

![img][img 1]

**退出登录**

之后在操作机上退出harbor登录，便于后面演示

### 退出harbor登录
    [root@k8s-node02 ~]# docker logout 172.16.1.110:5000
    Removing login credentials for 172.16.1.110:5000
    ### 拉取失败，需要先登录。表明完成准备工作
    [root@k8s-master secret]# docker pull 172.16.1.110:5000/k8s-secret/myapp:v1
    Error response from daemon: pull access denied for 172.16.1.110:5000/k8s-secret/myapp, repository does not exist or may require 'docker login': denied: requested access to the resource is denied

## pod直接下载镜像 ##

在yaml文件中指定image后，直接启动pod

[root@k8s-master secret]# pwd
    /root/k8s_practice/secret
    [root@k8s-master secret]# cat pod_secret_registry.yaml
    apiVersion: v1
    kind: Pod
    metadata:
      name: pod-secret-registry
    spec:
      containers:
      - name: myapp
        image: 172.16.1.110:5000/k8s-secret/myapp:v1

启动pod并查看状态

[root@k8s-master secret]# kubectl apply -f pod_secret_registry.yaml
    pod/pod-secret-registry created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get pod -o wide ### 可见镜像下载失败
    NAME                  READY   STATUS             RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
    pod-secret-registry   0/1     ImagePullBackOff   0          7s    10.244.2.161   k8s-node02   <none>           <none>
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl describe pod pod-secret-registry ### 查看pod详情
    Name:         pod-secret-registry
    Namespace:    default
    Priority:     0
    Node:         k8s-node02/172.16.1.112
    Start Time:   Mon, 08 Jun 2020 23:59:07 +0800
    Labels:       <none>
    Annotations:  kubectl.kubernetes.io/last-applied-configuration:
                    { "apiVersion":"v1","kind":"Pod","metadata":{ "annotations":{ },"name":"pod-secret-registry","namespace":"default"},"spec":{ "containers":[{ "i... Status: Pending IP: 10.244.2.161 IPs: IP: 10.244.2.161 Containers: myapp: Container ID: Image: 172.16.1.110:5000/k8s-secret/myapp:v1 Image ID: ……………… Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 23s default-scheduler Successfully assigned default/pod-secret-registry to k8s-node02 Normal BackOff 19s (x2 over 20s) kubelet, k8s-node02 Back-off pulling image "172.16.1.110:5000/k8s-secret/myapp:v1" Warning Failed 19s (x2 over 20s) kubelet, k8s-node02 Error: ImagePullBackOff Normal Pulling 9s (x2 over 21s) kubelet, k8s-node02 Pulling image "172.16.1.110:5000/k8s-secret/myapp:v1" Warning Failed 9s (x2 over 21s) kubelet, k8s-node02 Failed to pull image "172.16.1.110:5000/k8s-secret/myapp:v1": rpc error: code = Unknown desc = Error response from daemon: pull access denied for 172.16.1.110:5000/k8s-secret/myapp, repository does not exist or may require 'docker login': denied: requested access to the resource is denied
      Warning  Failed     9s (x2 over 21s)   kubelet, k8s-node02  Error: ErrImagePull
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl delete -f pod_secret_registry.yaml

可见拉取私有镜像失败。

## pod通过Secret下载镜像 ##

通过命令行创建Secret，并查看其描述信息

[root@k8s-master secret]# kubectl create secret docker-registry myregistrysecret --docker-server='172.16.1.110:5000' --docker-username='admin' --docker-password='Harbor12345'
    secret/myregistrysecret created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get secret
    NAME                  TYPE                                  DATA   AGE
    basic-auth            Opaque                                1      2d14h
    default-token-v48g4   kubernetes.io/service-account-token   3      27d
    myregistrysecret      kubernetes.io/dockerconfigjson        1      8s    # 刚刚创建的
    mysecret              Opaque                                2      118m
    tls-secret            kubernetes.io/tls                     2      3d4h
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get secret myregistrysecret -o yaml ### 查看详细信息
    apiVersion: v1
    data:
      .dockerconfigjson: eyJhdXRocyI6eyIxMC4wLjAuMTEwOjUwMDAiOnsidXNlcm5hbWUiOiJhZG1pbiIsInBhc3N3b3JkIjoiSGFyYm9yMTIzNDUiLCJhdXRoIjoiWVdSdGFXNDZTR0Z5WW05eU1USXpORFU9In19fQ==
    kind: Secret
    metadata:
      creationTimestamp: "2020-06-08T16:07:32Z"
      name: myregistrysecret
      namespace: default
      resourceVersion: "1004582"
      selfLink: /api/v1/namespaces/default/secrets/myregistrysecret
      uid: b95f4386-64bc-4ba3-b43a-08afb1c1eb9d
    type: kubernetes.io/dockerconfigjson
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl describe secret myregistrysecret ### 查看描述信息
    Name:         myregistrysecret
    Namespace:    default
    Labels:       <none>
    Annotations:  <none>
    
    Type:  kubernetes.io/dockerconfigjson
    
    Data
    ====
    .dockerconfigjson:  109 bytes

修改之前的yaml文件

[root@k8s-master secret]# cat pod_secret_registry.yaml
    apiVersion: v1
    kind: Pod
    metadata:
      name: pod-secret-registry
    spec:
      containers:
      - name: myapp
        image: 172.16.1.110:5000/k8s-secret/myapp:v1
      imagePullSecrets:
      - name: myregistrysecret

启动pod并查看状态

[root@k8s-master secret]# kubectl apply -f pod_secret_registry.yaml
    pod/pod-secret-registry created
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl get pod -o wide
    NAME                  READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
    pod-secret-registry   1/1     Running   0          8s    10.244.2.162   k8s-node02   <none>           <none>
    [root@k8s-master secret]#
    [root@k8s-master secret]# kubectl describe pod pod-secret-registry
    Name:         pod-secret-registry
    Namespace:    default
    Priority:     0
    Node:         k8s-node02/172.16.1.112
    Start Time:   Tue, 09 Jun 2020 00:22:40 +0800
    Labels:       <none>
    Annotations:  kubectl.kubernetes.io/last-applied-configuration:
                    { "apiVersion":"v1","kind":"Pod","metadata":{ "annotations":{ },"name":"pod-secret-registry","namespace":"default"},"spec":{ "containers":[{ "i... Status: Running IP: 10.244.2.162 IPs: IP: 10.244.2.162 Containers: myapp: Container ID: docker://ef4d42f1f1616a44c2a6c0a5a71333b27f46dfe76eb392962813a28d69150c00 Image: 172.16.1.110:5000/k8s-secret/myapp:v1 Image ID: docker-pullable://172.16.1.110:5000/k8s-secret/myapp@sha256:9eeca44ba2d410e54fccc54cbe9c021802aa8b9836a0bcf3d3229354e4c8870e Port: <none> Host Port: <none> State: Running Started: Tue, 09 Jun 2020 00:22:41 +0800 Ready: True Restart Count: 0 Environment: <none> Mounts: /var/run/secrets/kubernetes.io/serviceaccount from default-token-v48g4 (ro) Conditions: Type Status Initialized True Ready True ContainersReady True PodScheduled True Volumes: default-token-v48g4: Type: Secret (a volume populated by a Secret) SecretName: default-token-v48g4 Optional: false QoS Class: BestEffort Node-Selectors: <none> Tolerations: node.kubernetes.io/not-ready:NoExecute for 300s node.kubernetes.io/unreachable:NoExecute for 300s Events: Type Reason Age From Message ---- ------ ---- ---- ------- Normal Scheduled 22s default-scheduler Successfully assigned default/pod-secret-registry to k8s-node02 Normal Pulling 22s kubelet, k8s-node02 Pulling image "172.16.1.110:5000/k8s-secret/myapp:v1" Normal Pulled 22s kubelet, k8s-node02 Successfully pulled image "172.16.1.110:5000/k8s-secret/myapp:v1"
      Normal  Created    22s   kubelet, k8s-node02  Created container myapp
      Normal  Started    21s   kubelet, k8s-node02  Started container myapp

由上可见，通过secret认证后pod拉取私有镜像是可以的。

[Kubernetes K8S_Secret]: https://www.cnblogs.com/zhanglianghhh/p/13743024.html
[Harbor_Docker]: https://www.cnblogs.com/zhanglianghhh/p/13205786.html
[img]: /images/20221120/d234eaac63544056b3af209147f7dc4c.png
[img 1]: /images/20221120/4969bca284b147559d8cf464c31eafdf.png