Kubernetes K8S之存储Secret详解
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
[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
[root@k8s-master secret]# pwd
/root/k8s_practice/secret
[root@k8s-master secret]# cat secret.yaml
apiVersion: v1
kind: Secret
metadata:
name: mysecret
type: Opaque
data:
username: YWRtaW4=
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:
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
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
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
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
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
[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:
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:
Annotations:
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
[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:
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:
Host Port:
State: Running
Started: Tue, 09 Jun 2020 00:22:41 +0800
Ready: True
Restart Count: 0
Environment:
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:
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。
相关阅读
1、Harbor企业级私有Docker镜像仓库部署
