Secrets是Kubernetes中一种对象类型,用来保存密码、私钥、口令等敏感信息。与直接将敏感信息嵌入image、pod相比,Secrets更安全、更灵活,用户对敏感信息的控制力更强。同Docker对敏感信息的管理类似,首先用户创建Secrets将敏感信息加密后保存在集群中,创建pod时通过volume、环境变量引用Secrets。
Secret有三种类型:
base64 --decode
解码获得原始数据,因此安全性弱。Opaque类型的Secret,其value为base64编码后的值。
分别创建两个名为username.txt和password.txt的文件:
$ echo -n "admin" > ./username.txt
$ echo -n "1f2d1e2e67df" > ./password.txt
使用kubectl create secret
命令创建secret:
$ kubectl create secret generic db-user-pass --from-file=./username.txt --from-file=./password.txt
secret "db-user-pass" created
首先使用base64对数据进行编码:
$ echo -n 'admin' | base64
YWRtaW4=
$ echo -n '1f2d1e2e67df' | base64
MWYyZDFlMmU2N2Rm
创建一个类型为Secret的描述文件:
apiVersion: v1
kind: Secret
metadata:
name: mysecret
type: Opaque
data:
username: YWRtaW4=
password: MWYyZDFlMmU2N2Rm
$ kubectl create -f ./secret.yaml
secret "mysecret" created
查看此Secret:
$ kubectl get secret mysecret -o yaml
apiVersion: v1
data:
username: YWRtaW4=
password: MWYyZDFlMmU2N2Rm
kind: Secret
metadata:
creationTimestamp: 2016-01-22T18:41:56Z
name: mysecret
namespace: default
resourceVersion: "164619"
selfLink: /api/v1/namespaces/default/secrets/mysecret
uid: cfee02d6-c137-11e5-8d73-42010af00002
type: Opaque
创建好Secret之后,可以通过两种方式使用:
apiVersion: v1
kind: Pod
metadata:
name: mypod
spec:
containers:
- name: mypod
image: redis
volumeMounts:
- name: foo
mountPath: "/etc/foo"
readOnly: true
volumes:
- name: foo
secret:
secretName: mysecret
进入Pod查看挂载的Secret:
# ls /etc/secrets
password username
# cat /etc/secrets/username
admin
# cat /etc/secrets/password
1f2d1e2e67df
也可以只挂载Secret中特定的key:
apiVersion: v1
kind: Pod
metadata:
name: mypod
spec:
containers:
- name: mypod
image: redis
volumeMounts:
- name: foo
mountPath: "/etc/foo"
readOnly: true
volumes:
- name: foo
secret:
secretName: mysecret
items:
- key: username
path: my-group/my-username
在这种情况下:
apiVersion: v1
kind: Pod
metadata:
name: secret-env-pod
spec:
containers:
- name: mycontainer
image: redis
env:
- name: SECRET_USERNAME
valueFrom:
secretKeyRef:
name: mysecret
key: username
- name: SECRET_PASSWORD
valueFrom:
secretKeyRef:
name: mysecret
key: password
restartPolicy: Never
kubernetes.io/dockerconfigjson用于存储docker registry的认证信息,可以直接使用kubectl create secret
命令创建:
$ 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.
查看secret的内容:
$ kubectl get secret myregistrykey -o yaml
apiVersion: v1
data:
.dockercfg: eyJjY3IuY2NzLnRlbmNlbnR5dW4uY29tL3RlbmNlbnR5dW4iOnsidXNlcm5hbWUiOiIzMzIxMzM3OTk0IiwicGFzc3dvcmQiOiIxMjM0NTYuY29tIiwiZW1haWwiOiIzMzIxMzM3OTk0QHFxLmNvbSIsImF1dGgiOiJNek15TVRNek56azVORG94TWpNME5UWXVZMjl0In19
kind: Secret
metadata:
creationTimestamp: 2017-08-04T02:06:05Z
name: myregistrykey
namespace: default
resourceVersion: "1374279324"
selfLink: /api/v1/namespaces/default/secrets/myregistrykey
uid: 78f6a423-78b9-11e7-a70a-525400bc11f0
type: kubernetes.io/dockercfg
通过 base64 对 secret 中的内容解码:
$ echo "eyJjY3IuY2NzLnRlbmNlbnR5dW4uY29tL3RlbmNlbnR5dW4iOnsidXNlcm5hbWUiOiIzMzIxMzM3OTk0IiwicGFzc3dvcmQiOiIxMjM0NTYuY29tIiwiZW1haWwiOiIzMzIxMzM3OTk0QHFxLmNvbSIsImF1dGgiOiJNek15TVRNek56azVORG94TWpNME5UWXVZMjl0XXXX" | base64 --decode
{"ccr.ccs.tencentyun.com/XXXXXXX":{"username":"3321337XXX","password":"123456.com","email":"3321337XXX@qq.com","auth":"MzMyMTMzNzk5NDoxMjM0NTYuY29t"}}
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
用于被 serviceaccount 引用。serviceaccout 创建时 Kubernetes 会默认创建对应的 secret。Pod 如果使用了 serviceaccount,对应的 secret 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