Kubernetes m6S之存储点Secret精解

Z时代
2024-01-10
分类：技术分享

K8S之存储Secret概述与类型说明，并详解常用Secret示例

主机配置规划

服务器名称(hostname)	系统版本	配置	内网IP	外网IP(模拟)
k8s-master	CentOS7.7	2C/4G/20G	172.16.1.110	10.0.0.110
k8s-node01	CentOS7.7	2C/4G/20G	172.16.1.111	10.0.0.111
k8s-node02	CentOS7.7	2C/4G/20G	172.16.1.112	10.0.0.112

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

 1 [root@k8s-master ~]# kubectl get pod -A | grep'kube-proxy'
 2 kube-system            kube-proxy-6bfh7                             1/1     Running   12         7d3h
 3 kube-system            kube-proxy-6vfkf                             1/1     Running   11         7d3h
 4 kube-system            kube-proxy-bvl9n                             1/1     Running   11         7d3h
 5 [root@k8s-master ~]#
 6 [root@k8s-master ~]# kubectl exec -it -n kube-system kube-proxy-6bfh7 -- /bin/sh
 7 # ls -l /run/secrets/kubernetes.io/serviceaccount
 8 total 0
 9 lrwxrwxrwx 1 root root 13 Jun  813:39 ca.crt -> ..data/ca.crt
10 lrwxrwxrwx 1 root root 16 Jun  813:39 namespace -> ..data/namespace
11 lrwxrwxrwx 1 root root 12 Jun  813:39 token -> ..data/token

Opaque Secret

创建secret

手动加密，基于base64加密

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

yaml文件

1 [root@k8s-master secret]# pwd

2 /root/k8s_practice/secret

3 [root@k8s-master secret]# cat secret.yaml

4apiVersion: v1

5kind: Secret

6metadata:

7 name: mysecret

8type: Opaque

9data:

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

 1 [root@k8s-master secret]# kubectl apply -f secret.yaml
 2 secret/mysecret created
 3 [root@k8s-master secret]#
 4 [root@k8s-master secret]# kubectl get secret   ### 查看默认名称空间的secret简要信息
 5NAME                  TYPE                                  DATA   AGE
 6 basic-auth            Opaque                                1      2d12h
 7 default-token-v48g4   kubernetes.io/service-account-token   3      27d
 8 mysecret              Opaque                                2      23s  ### 可见已创建
 9 tls-secret            kubernetes.io/tls                     2      3d2h
10 [root@k8s-master secret]#
11 [root@k8s-master secret]# kubectl get secret mysecret -o yaml     ### 查看mysecret详细信息
12apiVersion: v1
13data:
14  password: MWYyZDFlMmU2N2Rm
15   username: YWRtaW4=
16kind: Secret
17metadata:
18  annotations:
19     kubectl.kubernetes.io/last-applied-configuration: |
20       {"apiVersion":"v1","data":{"password":"MWYyZDFlMmU2N2Rm","username":"YWRtaW4="},"kind":"Secret","metadata":{"annotations":{},"name":"mysecret","namespace":"default"},"type":"Opaque"}
21   creationTimestamp: "2020-06-08T14:08:59Z"
22  name: mysecret
23  namespace: default
24   resourceVersion: "987419"
25   selfLink: /api/v1/namespaces/default/secrets/mysecret
26   uid: 27b58929-71c4-495b-99a5-0d411910a529
27type: Opaque
28 [root@k8s-master secret]#
29 [root@k8s-master secret]# kubectl describe secret mysecret     ### 查看描述信息
30Name:         mysecret
31Namespace:    default
32 Labels:       <none>
33Annotations:
34Type:         Opaque
35
36Data
37 ====
38 password:  12 bytes
39 username:  5 bytes

将Secret挂载到Volume中

yaml文件

1 [root@k8s-master secret]# pwd

2 /root/k8s_practice/secret

3 [root@k8s-master secret]# cat pod_secret_volume.yaml

4apiVersion: v1

5kind: Pod

6metadata:

7 name: pod-secret-volume

8spec:

9 containers:

10 - name: myapp

11 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1

12 volumeMounts:

13 - name: secret-volume

14 mountPath: /etc/secret

15 readOnly: true

16 volumes:

17 - name: secret-volume

18 secret:

19 secretName: mysecret

启动pod并查看状态

1 [root@k8s-master secret]# kubectl apply -f pod_secret_volume.yaml
2 pod/pod-secret-volume created
3 [root@k8s-master secret]#
4 [root@k8s-master secret]# kubectl get pod -o wide
5NAME                READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
6 pod-secret-volume   1/1     Running   0          16s   10.244.2.159   k8s-node02   <none>           <none>

查看secret信息

1 [root@k8s-master secret]# kubectl exec -it pod-secret-volume -- /bin/sh

2 / # ls /etc/secret

3password username

4 / #

5 / # cat /etc/secret/username

6 admin/ #

7 / #

8 / # cat /etc/secret/password

9 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

1 [root@k8s-master secret]# pwd

2 /root/k8s_practice/secret

3 [root@k8s-master secret]# cat pod_secret_env.yaml

4apiVersion: v1

5kind: Pod

6metadata:

7 name: pod-secret-env

8spec:

9 containers:

10 - name: myapp

11 image: registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1

12env:

13 - name: SECRET_USERNAME

14 valueFrom:

15 secretKeyRef:

16 name: mysecret

17 key: username

18 - name: SECRET_PASSWORD

19 valueFrom:

20 secretKeyRef:

21 name: mysecret

22 key: password

23 restartPolicy: Never

启动pod并查看状态

1 [root@k8s-master secret]# kubectl apply -f pod_secret_env.yaml
2 pod/pod-secret-env created
3 [root@k8s-master secret]#
4 [root@k8s-master secret]# kubectl get pod -o wide
5NAME             READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
6 pod-secret-env1/1     Running   0          6s    10.244.2.160   k8s-node02   <none>           <none>

查看secret信息

1 [root@k8s-master secret]# kubectl exec -it pod-secret-env -- /bin/sh

2 / # env

3………………

4 HOME=/root

5 SECRET_PASSWORD=1f2d1e2e67df ### secret信息

6 MYAPP_SVC_PORT_80_TCP=tcp://10.98.57.156:80

7 TERM=xterm

8 NGINX_VERSION=1.12.2

9 KUBERNETES_PORT_443_TCP_ADDR=10.96.0.1

10 PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

11 KUBERNETES_PORT_443_TCP_PORT=443

12 KUBERNETES_PORT_443_TCP_PROTO=tcp

13 MYAPP_SVC_SERVICE_HOST=10.98.57.156

14 SECRET_USERNAME=admin ### secret信息

15 KUBERNETES_PORT_443_TCP=tcp://10.96.0.1:443

16 ………………

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部分配置文件信息

1 [root@k8s-master harbor]# pwd

2 /root/App/harbor

3 [root@k8s-master harbor]# vim harbor.yml

4 # Configuration file of Harbor

5hostname: 172.16.1.110

7# http related config

8http:

9 # port for http, default is 80. If https enabled, this port will redirect to https port

10 port: 5000

12# https related config

13https:

14 # https port for harbor, default is 443

15 port: 443

16 # The path of cert and key files for nginx

17 certificate: /etc/harbor/cert/httpd.crt

18 private_key: /etc/harbor/cert/httpd.key

19 harbor_admin_password: Harbor12345

启动harbor后客户端http设置

集群所有机器都要操作

 1 [root@k8s-master ~]# vim /etc/docker/daemon.json
 2{
 3"exec-opts": ["native.cgroupdriver=systemd"],
 4"log-driver": "json-file",
 5"log-opts": {
 6"max-size": "100m"
 7  },
 8"insecure-registries": ["172.16.1.110:5000"]
 9}
10 [root@k8s-master ~]#
11 [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

镜像上传

1 docker pull registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1
2 docker tag registry.cn-beijing.aliyuncs.com/google_registry/myapp:v1 172.16.1.110:5000/k8s-secret/myapp:v1
3# 登录
4 docker login172.16.1.110:5000 -u admin -p Harbor12345
5# 上传
6 docker push 172.16.1.110:5000/k8s-secret/myapp:v1

退出登录

之后在操作机上退出harbor登录，便于后面演示

1### 退出harbor登录
2 [root@k8s-node02 ~]# docker logout 172.16.1.110:5000
3 Removing login credentials for172.16.1.110:5000
4### 拉取失败，需要先登录。表明完成准备工作
5 [root@k8s-master secret]# docker pull 172.16.1.110:5000/k8s-secret/myapp:v1
6 Error response from daemon: pull access denied for172.16.1.110:5000/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

1 [root@k8s-master secret]# pwd

2 /root/k8s_practice/secret

3 [root@k8s-master secret]# cat pod_secret_registry.yaml

4apiVersion: v1

5kind: Pod

6metadata:

7 name: pod-secret-registry

8spec:

9 containers:

10 - name: myapp

11 image: 172.16.1.110:5000/k8s-secret/myapp:v1

启动pod并查看状态

 1 [root@k8s-master secret]# kubectl apply -f pod_secret_registry.yaml
 2 pod/pod-secret-registry created
 3 [root@k8s-master secret]#
 4 [root@k8s-master secret]# kubectl get pod -o wide     ### 可见镜像下载失败
 5NAME                  READY   STATUS             RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
 6 pod-secret-registry   0/1     ImagePullBackOff   0          7s    10.244.2.161   k8s-node02   <none>           <none>
 7 [root@k8s-master secret]#
 8 [root@k8s-master secret]# kubectl describe pod pod-secret-registry     ### 查看pod详情
 9 Name:         pod-secret-registry
10Namespace:    default
11 Priority:     0
12 Node:         k8s-node02/172.16.1.112
13 Start Time:   Mon, 08 Jun 202023:59:07 +0800
14 Labels:       <none>
15 Annotations:  kubectl.kubernetes.io/last-applied-configuration:
16                 {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"pod-secret-registry","namespace":"default"},"spec":{"containers":[{"i...
17Status:       Pending
18 IP:           10.244.2.161
19IPs:
20   IP:  10.244.2.161
21Containers:
22  myapp:
23    Container ID:
24     Image:          172.16.1.110:5000/k8s-secret/myapp:v1
25    Image ID:
26………………
27Events:
28  Type     Reason     Age                From                 Message
29   ----     ------     ----               ----                 -------
30   Normal   Scheduled  23s                default-scheduler    Successfully assigned default/pod-secret-registry to k8s-node02
31   Normal   BackOff    19s (x2 over 20s)  kubelet, k8s-node02  Back-off pulling image "172.16.1.110:5000/k8s-secret/myapp:v1"
32   Warning  Failed     19s (x2 over 20s)  kubelet, k8s-node02  Error: ImagePullBackOff
33   Normal   Pulling    9s (x2 over 21s)   kubelet, k8s-node02  Pulling image "172.16.1.110:5000/k8s-secret/myapp:v1"
34   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 for172.16.1.110:5000/k8s-secret/myapp, repository does not exist or may require 'docker login': denied: requested access to the resource is denied
35   Warning  Failed     9s (x2 over 21s)   kubelet, k8s-node02  Error: ErrImagePull
36 [root@k8s-master secret]#
37 [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

1 [root@k8s-master secret]# kubectl create secret docker-registry myregistrysecret --docker-server='172.16.1.110:5000' --docker-username='admin' --docker-password='Harbor12345'

2 secret/myregistrysecret created

3 [root@k8s-master secret]#

4 [root@k8s-master secret]# kubectl get secret

5NAME TYPE DATA AGE

6 basic-auth Opaque 1 2d14h

7 default-token-v48g4 kubernetes.io/service-account-token 3 27d

8 myregistrysecret kubernetes.io/dockerconfigjson 1 8s # 刚刚创建的

9 mysecret Opaque 2 118m

10 tls-secret kubernetes.io/tls 2 3d4h

11 [root@k8s-master secret]#

12 [root@k8s-master secret]# kubectl get secret myregistrysecret -o yaml ### 查看详细信息

13apiVersion: v1

14data:

15 .dockerconfigjson: eyJhdXRocyI6eyIxMC4wLjAuMTEwOjUwMDAiOnsidXNlcm5hbWUiOiJhZG1pbiIsInBhc3N3b3JkIjoiSGFyYm9yMTIzNDUiLCJhdXRoIjoiWVdSdGFXNDZTR0Z5WW05eU1USXpORFU9In19fQ==

16kind: Secret

17metadata:

18 creationTimestamp: "2020-06-08T16:07:32Z"

19 name: myregistrysecret

20 namespace: default

21 resourceVersion: "1004582"

22 selfLink: /api/v1/namespaces/default/secrets/myregistrysecret

23 uid: b95f4386-64bc-4ba3-b43a-08afb1c1eb9d

24 type: kubernetes.io/dockerconfigjson

25 [root@k8s-master secret]#

26 [root@k8s-master secret]# kubectl describe secret myregistrysecret ### 查看描述信息

27Name: myregistrysecret

28Namespace: default

29 Labels: <none>

30 Annotations: <none>

32 Type: kubernetes.io/dockerconfigjson

34Data

35 ====

36 .dockerconfigjson: 109 bytes

修改之前的yaml文件

 1 [root@k8s-master secret]# cat pod_secret_registry.yaml
 2apiVersion: v1
 3kind: Pod
 4metadata:
 5   name: pod-secret-registry
 6spec:
 7  containers:
 8   - name: myapp
 9     image: 172.16.1.110:5000/k8s-secret/myapp:v1
10  imagePullSecrets:
11   - name: myregistrysecret

启动pod并查看状态

 1 [root@k8s-master secret]# kubectl apply -f pod_secret_registry.yaml
 2 pod/pod-secret-registry created
 3 [root@k8s-master secret]#
 4 [root@k8s-master secret]# kubectl get pod -o wide
 5NAME                  READY   STATUS    RESTARTS   AGE   IP             NODE         NOMINATED NODE   READINESS GATES
 6 pod-secret-registry   1/1     Running   0          8s    10.244.2.162   k8s-node02   <none>           <none>
 7 [root@k8s-master secret]#
 8 [root@k8s-master secret]# kubectl describe pod pod-secret-registry
 9 Name:         pod-secret-registry
10Namespace:    default
11 Priority:     0
12 Node:         k8s-node02/172.16.1.112
13 Start Time:   Tue, 09 Jun 202000:22:40 +0800
14 Labels:       <none>
15 Annotations:  kubectl.kubernetes.io/last-applied-configuration:
16                 {"apiVersion":"v1","kind":"Pod","metadata":{"annotations":{},"name":"pod-secret-registry","namespace":"default"},"spec":{"containers":[{"i...
17Status:       Running
18 IP:           10.244.2.162
19IPs:
20   IP:  10.244.2.162
21Containers:
22  myapp:
23     Container ID:   docker://ef4d42f1f1616a44c2a6c0a5a71333b27f46dfe76eb392962813a28d69150c00
24     Image:          172.16.1.110:5000/k8s-secret/myapp:v1
25     Image ID:       docker-pullable://172.16.1.110:5000/k8s-secret/myapp@sha256:9eeca44ba2d410e54fccc54cbe9c021802aa8b9836a0bcf3d3229354e4c8870e
26     Port:           <none>
27     Host Port:      <none>
28    State:          Running
29       Started:      Tue, 09 Jun 202000:22:41 +0800
30    Ready:          True
31     Restart Count:  0
32     Environment:    <none>
33    Mounts:
34       /var/run/secrets/kubernetes.io/serviceaccount from default-token-v48g4 (ro)
35Conditions:
36  Type              Status
37  Initialized       True
38  Ready             True
39  ContainersReady   True
40  PodScheduled      True
41Volumes:
42   default-token-v48g4:
43    Type:        Secret (a volume populated by a Secret)
44     SecretName:  default-token-v48g4
45     Optional:    false
46QoS Class:       BestEffort
47 Node-Selectors:  <none>
48 Tolerations:     node.kubernetes.io/not-ready:NoExecute for 300s
49                  node.kubernetes.io/unreachable:NoExecute for 300s
50Events:
51  Type    Reason     Age   From                 Message
52   ----    ------     ----  ----                 -------
53   Normal  Scheduled  22s   default-scheduler    Successfully assigned default/pod-secret-registry to k8s-node02
54   Normal  Pulling    22s   kubelet, k8s-node02  Pulling image "172.16.1.110:5000/k8s-secret/myapp:v1"
55   Normal  Pulled     22s   kubelet, k8s-node02  Successfully pulled image "172.16.1.110:5000/k8s-secret/myapp:v1"
56   Normal  Created    22s   kubelet, k8s-node02  Created container myapp
57   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 m6S之存储点Secret精解

主机配置规划

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

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