Secret

Secret解决了密码、token、密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。

Secret类型

Secret有三种类型:

  • 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、密钥等;
  • kubernetes.io/dockerconfigjson:用来存储私有docker registry的认证信息。

Opaque Secret

Opaque类型的数据是一个map类型,要求value是base64编码格式:

$ echo -n "admin" | base64
YWRtaW4=
$ echo -n "1f2d1e2e67df" | base64
MWYyZDFlMmU2N2Rm

secrets.yml

apiVersion: v1
kind: Secret
metadata:
  name: mysecret
type: Opaque
data:
  password: MWYyZDFlMmU2N2Rm
  username: YWRtaW4=

创建secret:kubectl create -f secrets.yml

如果是从文件创建secret,则可以用更简单的kubectl命令,比如创建tls的secret:

$ kubectl create secret generic helloworld-tls \
  --from-file=key.pem \
  --from-file=cert.pem

Secret引用

创建好secret之后,有两种方式来使用它:

  • 以Volume方式
  • 以环境变量方式

将Secret挂载到Volume中

apiVersion: v1
kind: Pod
metadata:
  labels:
    name: db
  name: db
spec:
  volumes:
  - name: secrets
    secret:
      secretName: mysecret
  containers:
  - image: gcr.io/my_project_id/pg:v1
    name: db
    volumeMounts:
    - name: secrets
      mountPath: "/etc/secrets"
      readOnly: true
    ports:
    - name: cp
      containerPort: 5432
      hostPort: 5432

将Secret导出到环境变量中

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: wordpress-deployment
spec:
  replicas: 2
  strategy:
      type: RollingUpdate
  template:
    metadata:
      labels:
        app: wordpress
        visualize: "true"
    spec:
      containers:
      - name: "wordpress"
        image: "wordpress"
        ports:
        - containerPort: 80
        env:
        - name: WORDPRESS_DB_USER
          valueFrom:
            secretKeyRef:
              name: mysecret
              key: username
        - name: WORDPRESS_DB_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysecret
              key: password

kubernetes.io/dockerconfigjson

可以直接用kubectl命令来创建用于docker registry认证的secret:

$ kubectl create secret docker-registry myregistrykey --docker-server=DOCKER_REGISTRY_SERVER --docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD --docker-email=DOCKER_EMAIL
secret "myregistrykey" created.

也可以直接读取~/.dockercfg的内容来创建:

$ kubectl create secret docker-registry myregistrykey \
  --from-file="~/.dockercfg"

在创建Pod的时候,通过imagePullSecrets来引用刚创建的myregistrykey:

apiVersion: v1
kind: Pod
metadata:
  name: foo
spec:
  containers:
    - name: foo
      image: janedoe/awesomeapp:v1
  imagePullSecrets:
    - name: myregistrykey

Service Account

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。

$ kubectl run nginx --image nginx
deployment "nginx" created
$ kubectl get pods
NAME                     READY     STATUS    RESTARTS   AGE
nginx-3137573019-md1u2   1/1       Running   0          13s
$ kubectl exec nginx-3137573019-md1u2 ls /run/secrets/kubernetes.io/serviceaccount
ca.crt
namespace
token

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