kubernetes资源类型--secret和Service Account

secret

概念

secret对象类型主要目的是保存和处理敏感信息/私密数据，比如密码，OAuth tokens，ssh keys等信息。将这些信息放在secret对象中比 直接放在pod或docker image中更安全，也更方便使用。

一个已经创建好的secrets对象有两种方式被pod对象使用，其一，在container中的volume对象里以file的形式被使用，其二，在pull images时被kubelet使用。

类型

Opaque任意字符串，默认类型

kubernetes.io/service-account-token:作用于ServiceAccount

kubernetes.io/dockercfg:作用于Docker registry，用户下载docker镜像认证使用

Opaque

创建

文件

实现把需要加密的内容实现base64编码

echo -n lykops | base64

bHlrb3Bz

echo -n 1qaz2wsx | base64

MXFhejJ3c3g=

然后写入lykops-secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: test-secret
  namespace: default
type: Opaque
data:
  password: MXFhejJ3c3g=
  username: bHlrb3Bz

导入kubectl create -f lykops-secret.yaml

命令行

kubectl createsecret generic lykops --secret --from-literal=username=lykops--from-literal=password=1qaz2wsx

pod引用

cat << EOF > lykops-secret.yaml
apiVersion: v1
kind: Pod
metadata:
 name: lykops-secret-pod
 labels:
   software: apache
   project: lykops
   app: lykops-secret-pod
   version: v1
spec:
 containers:
    -name: lykops-secret-pod
     image: web:apache
     command: ['sh' , '/etc/run.sh']
     env:
       - name: SECRET_USERNAME
         valueFrom:
           secretKeyRef:
             name: lykops-secret
             key: username
       - name: SECRET_PASSWORD
         valueFrom:
           secretKeyRef:
             name: lykops-secret
             key: password

EOF

kubectl create -f lykops-secret-pod.yaml

然后进入pod

kubectl exec -it lykops-secret-pod /bin/bash

执行env | grep -i '^SECRET_'

SECRET_USERNAME=lykops

SECRET_PASSWORD=1qaz2wsx

imagePullSecrets

当在需要安全验证的环境中拉取镜像时，需要通过用户名和密码。

apiVersion: v1
kind: Secret
metadata:
 name: myregistrykey
 namespace: awesomeapps
data:
 .dockerconfigjson:UmVhbGx5IHJlYWxseSByZWVlZWVlZWVlZWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWFhYWxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGxsbGx5eXl5eXl5eXl5eXl5eXl5eXl5eSBsbGxsbGxsbGxsbGxsbG9vb29vb29vb29vb29vb29vb29vb29vb29vb25ubm5ubm5ubm5ubm5ubm5ubm5ubm5ubmdnZ2dnZ2dnZ2dnZ2dnZ2dnZ2cgYXV0aCBrZXlzCg==
type: kubernetes.io/dockerconfigjson

·或者直接通过命令创建

kubectl create secret docker-registrymyregistrykey --docker-server=DOCKER_REGISTRY_SERVER--docker-username=DOCKER_USER --docker-password=DOCKER_PASSWORD--docker-email=DOCKER_EMAIL

·接下来拉取镜像的时候，就可以使用了

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

·其实本质上还是kubelet把这个认证放到了docker的目录下面，如下：

Service Account

概念

Service Account（以下简称SA）的使用场景：运行在pod里的进程需要调用K8S API以及非K8S API的其它服务。SA

cat ~/.docker/config.json
{
   "auths": {
       "10.39.0.118": {
           "auth": "Y2hlbm1vOmNtMTM4MTE2NjY3ODY="
       },
       "10.39.0.12:5000": {
           "auth": "dXNlcjAxOjEyMzQ1YQ=="
       },
       "http://10.39.0.12:5000": {
           "auth": "dXNlcjAxOjEyMzQ1YQ=="
       }
    }
}

并不是给K8S集群的用户使用的，而是给pod里面的进程使用的，它为pod提供必要的身份认证。

如果K8S开启了SA（位于/etc/kubernetes/controller-manager的KUBE_ADMISSION_CONTROL="--admission-control=NamespaceLifecycle,NamespaceExists,LimitRanger,SecurityContextDeny,ServiceAccount,ResourceQuota"），那么会在每个namespace下面都会创建一个默认的default的SA。

配置

当用户在namespace下创建pod时会默认使用sa。

……
 volumes:
  -name: default-token-rsf8r
   secret:
     defaultMode: 420
      secretName:default-token-rsf8r

具体看一下secret

kubectl get secret default-token-rsf8r -oyaml
apiVersion: v1
data:
 ca.crt:LS0tLS1CRUdJTiBDRVJUSUZJQ0FURS0tLS0tCk1JSUR2akNDQXFhZ0F3SUJBZ0lVZlpvZDJtSzNsa3JiMzR3NDhhUmtOc0pVVDJjd0RRWUpLb1pJaHZjTkFRRUwKQlFBd1pURUxNQWtHQTFVRUJoTUNRMDR4RURBT0JnTlZCQWdUQjBKbGFVcHBibWN4RURBT0JnTlZCQWNUQjBKbAphVXBwYm1jeEREQUtCZ05WQkFvVEEyczRjekVQTUEwR0ExVUVDeE1HVTNsemRHVnRNUk13RVFZRFZRUURFd3ByCmRXSmxjbTVsZEdWek1CNFhEVEUzTURVd01qQTNNekF3TUZvWERUSXlNRFV3TVRBM016QXdNRm93WlRFTE1Ba0cKQTFVRUJoTUNRMDR4RURBT0JnTlZCQWdUQjBKbGFVcHBibWN4RURBT0JnTlZCQWNUQjBKbGFVcHBibWN4RERBSwpCZ05WQkFvVEEyczRjekVQTUEwR0ExVUVDeE1HVTNsemRHVnRNUk13RVFZRFZRUURFd3ByZFdKbGNtNWxkR1Z6Ck1JSUJJakFOQmdrcWhraUc5dzBCQVFFRkFBT0NBUThBTUlJQkNnS0NBUUVBc2E5Zk1HVGd2MGl0YnlZcHoycXkKOThKWktXdWdFL0VPbXRYS2ExT0Y3ekUxSFh1cDFOVG8rNkhvUEFuR3hhVzg4Q0s0TENrbWhNSGFLdUxnT3IvVApOMGphdnc5YWlPeVdYR1hXUUxVN3U0aVhoaDV6a2N4bmZxRW9JOW9JV2dMTzVEL3hBL0tnZzRQZDRMeFdqMkFQCk4rcVdxQ2crU3BrdkpIQUZWL3IyTk1BbEIzNHBrK0t5djVQMDJSQmd6Y2xTeSs5OUxDWnlIQ1VocGl0TFFabHoKdUNmeGtBeUNoWFcxMWNKdVFtaDM4aFVKa0dhUW9OVDVSNmtoRTArenJDVjVkWnNVMVZuR0FydWxaWXpJY3kregpkeUZpYWYyaitITyt5blg4RUNySzR1TUF3Nk4zN1pnNjRHZVRtbk5EWmVDTTlPelk5czBOVzc1dHU5bHJPZTVqCnZRSURBUUFCbzJZd1pEQU9CZ05WSFE4QkFmOEVCQU1DQVFZd0VnWURWUjBUQVFIL0JBZ3dCZ0VCL3dJQkFqQWQKQmdOVkhRNEVGZ1FVK2RqMThRUkZyMWhKMVhGb1VyYUVVRnpEeVRBd0h3WURWUjBqQkJnd0ZvQVUrZGoxOFFSRgpyMWhKMVhGb1VyYUVVRnpEeVRBd0RRWUpLb1pJaHZjTkFRRUxCUUFEZ2dFQkFBazQ4ODZBa0Fpa3VBVWRiOWU1CitldkVXVVFFaTIyTmc4REhmVTVSbXppU2ZhVllFQ1FuTlBUREprMmYvTm1Kb3RUVWxRZS9Ec3BkNEk1TFova1IKMGI2b1VoZkdmTkVOOXVObkkvZEgzOFBjUTNDaWtVeHhaeFRYTytaaldxcGNHZTRLNzZtaWd2ZWhQR2Z1VUNzQwp0UmZkZDM2YkhnRjN4MzRCWnc5MStDQ2VKQzBSWmNjVENqcHFHUEZFQlM3akJUVUlRVjNodnZycWJMV0hNeTJuCnFIck94UFI1eFkrRU5SQ0xzVWNSdk9icUhBK1g0c1BTdzBwMWpROXNtK1lWNG1ybW9Gd1RyS09kK2FqTVhzVXkKL3ZRYkRzNld4RWkxZ2ZvR3BxZFN6U1k0MS9IWHovMjZWNlFWazJBajdQd0FYZmszYk1wWHdDamRXRG4xODhNbQpXSHM9Ci0tLS0tRU5EIENFUlRJRklDQVRFLS0tLS0K
 namespace: ZGVmYXVsdA==
 token: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
kind: Secret
metadata:
 annotations:
   kubernetes.io/service-account.name: default
   kubernetes.io/service-account.uid: 0de23575-2f02-11e7-98d0-5254c4628ad9
 name: default-token-rsf8r
 namespace: default
 resourceVersion: "12551"
 selfLink: /api/v1/namespaces/default/secrets/default-token-rsf8r
  uid:75c0a236-2f02-11e7-98d0-5254c4628ad9
type: kubernetes.io/service-account-token

上面的内容是经过base64加密过后的，直接进入容器内：

ls -l /var/run/secrets/kubernetes.io/serviceaccount/
total 0
lrwxrwxrwx   1 root     root            13 May  4 23:57 ca.crt -> ..data/ca.crt
lrwxrwxrwx   1 root     root            16 May  4 23:57 namespace -> ..data/namespace
lrwxrwxrwx   1 root     root            12 May  4 23:57 token -> ..data/token

可以看到已将ca.crt 、namespace和token放到容器内了，那么这个容器就可以通过https的请求访问apiserver了。