通过serviceAccount的secret访问kubernetes API Server

本文简单介绍如何通过serviceAccount访问kubernetes API server，不会详细介绍serviceAccount、role、 roleBinding、clusterRole以及clusterRoleBinding。

简单描述：serviceAccount与role通过roleBinding或者clusterRoleBinding关联后就获得访问指定资源的权限，就如同我们应用程序中将权限添加一个组（role）， 然后让用户（serviceAccount）属于（roleBinding）某个组（role）。

前提

我已经创建了一个yqaccount的serviceAccount，并且将他和cluster-admin role关联了。

创建serviceAccount以及关联的命令如下：

kubectl create serviceaccount yqaccount  # 创建yqaccount serviceAccount

kubectl create clusterrolebinding cluster-admin-yqaccount  --clusterrole=cluster-admin --serviceaccount=default:yqaccount   # 将yqaccount serviceAccount与cluster-admin 进行绑定

           

备注，我都是在default namespace中操作的，所以不用特别指定namespace

设置环境变量

通过设置环境变量生成方位API server需要的token和整数

export SERVICE_ACCOUNT=yqaccount
export SECRET=$(kubectl get serviceaccount ${SERVICE_ACCOUNT} -o json | jq -Mr '.secrets[].name | select(contains("token"))')
export TOKEN=$(kubectl get secret ${SECRET} -o json | jq -Mr '.data.token' | base64 -d)
kubectl get secret ${SECRET} -o json | jq -Mr '.data["ca.crt"]' | base64 -d > /tmp/ca.crt
export APISERVER=https://$(kubectl -n default get endpoints kubernetes --no-headers | awk '{ print $2 }')
           

关于jq的用法请参考：https://stedolan.github.io/jq/manual/

这里简单解释一下-Mr， 其中-M表示不带颜色的输出（jq处理的json默认是带颜色输出的）， -r表示的原始消息，不需要加上双引号。

通过curl访问restAPI

列出当前default namespace下的pod， 然后通过jq将其中pod的name打印出来

其他rest API地址可以通查询kubernetes文档得到

API文档 https://kubernetes.io/docs/reference/using-api/api-concepts/， kubernetes.io/third_party/swagger-ui/

例如查看pod日志的rest api是https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#-strong-misc-operations-pod-v1-core-strong-

https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#-strong-misc-operations-pod-v1-core-strong-

HTTP Request

GET /api/v1/namespaces/{namespace}/pods/{name}/log

额外部分

jq获取secret

jq获取从secret获取token

jq从secret获取ca证书

[[email protected] ~]# curl -s $APISERVER  --header "Authorization: Bearer $TOKEN" --cacert /tmp/ca.crt
{
  "paths": [
    "/api",
    "/api/v1",
    "/apis",
    "/apis/",
    "/apis/admissionregistration.k8s.io",
    "/apis/admissionregistration.k8s.io/v1",
    "/apis/admissionregistration.k8s.io/v1beta1",
    "/apis/apiextensions.k8s.io",
    "/apis/apiextensions.k8s.io/v1",
    "/apis/apiextensions.k8s.io/v1beta1",
    "/apis/apiregistration.k8s.io",
    "/apis/apiregistration.k8s.io/v1",
    "/apis/apiregistration.k8s.io/v1beta1",
    "/apis/apps",
    "/apis/apps/v1",
    "/apis/authentication.k8s.io",
    "/apis/authentication.k8s.io/v1",
    "/apis/authentication.k8s.io/v1beta1",
    "/apis/authorization.k8s.io",
    "/apis/authorization.k8s.io/v1",
    "/apis/authorization.k8s.io/v1beta1",
    "/apis/autoscaling",
    "/apis/autoscaling/v1",
    "/apis/autoscaling/v2beta1",
    "/apis/autoscaling/v2beta2",
    "/apis/batch",
    "/apis/batch/v1",
    "/apis/batch/v1beta1",
    "/apis/certificates.k8s.io",
    "/apis/certificates.k8s.io/v1beta1",
    "/apis/coordination.k8s.io",
    "/apis/coordination.k8s.io/v1",
    "/apis/coordination.k8s.io/v1beta1",
    "/apis/discovery.k8s.io",
    "/apis/discovery.k8s.io/v1beta1",
    "/apis/events.k8s.io",
    "/apis/events.k8s.io/v1beta1",
    "/apis/extensions",
    "/apis/extensions/v1beta1",
    "/apis/networking.k8s.io",
    "/apis/networking.k8s.io/v1",
    "/apis/networking.k8s.io/v1beta1",
    "/apis/node.k8s.io",
    "/apis/node.k8s.io/v1beta1",
    "/apis/policy",
    "/apis/policy/v1beta1",
    "/apis/rbac.authorization.k8s.io",
    "/apis/rbac.authorization.k8s.io/v1",
    "/apis/rbac.authorization.k8s.io/v1beta1",
    "/apis/scheduling.k8s.io",
    "/apis/scheduling.k8s.io/v1",
    "/apis/scheduling.k8s.io/v1beta1",
    "/apis/storage.k8s.io",
    "/apis/storage.k8s.io/v1",
    "/apis/storage.k8s.io/v1beta1",
    "/healthz",
    "/healthz/autoregister-completion",
    "/healthz/etcd",
    "/healthz/log",
    "/healthz/ping",
    "/healthz/poststarthook/apiservice-openapi-controller",
    "/healthz/poststarthook/apiservice-registration-controller",
    "/healthz/poststarthook/apiservice-status-available-controller",
    "/healthz/poststarthook/bootstrap-controller",
    "/healthz/poststarthook/crd-informer-synced",
    "/healthz/poststarthook/generic-apiserver-start-informers",
    "/healthz/poststarthook/kube-apiserver-autoregistration",
    "/healthz/poststarthook/rbac/bootstrap-roles",
    "/healthz/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/healthz/poststarthook/start-apiextensions-controllers",
    "/healthz/poststarthook/start-apiextensions-informers",
    "/healthz/poststarthook/start-cluster-authentication-info-controller",
    "/healthz/poststarthook/start-kube-aggregator-informers",
    "/healthz/poststarthook/start-kube-apiserver-admission-initializer",
    "/livez",
    "/livez/autoregister-completion",
    "/livez/etcd",
    "/livez/log",
    "/livez/ping",
    "/livez/poststarthook/apiservice-openapi-controller",
    "/livez/poststarthook/apiservice-registration-controller",
    "/livez/poststarthook/apiservice-status-available-controller",
    "/livez/poststarthook/bootstrap-controller",
    "/livez/poststarthook/crd-informer-synced",
    "/livez/poststarthook/generic-apiserver-start-informers",
    "/livez/poststarthook/kube-apiserver-autoregistration",
    "/livez/poststarthook/rbac/bootstrap-roles",
    "/livez/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/livez/poststarthook/start-apiextensions-controllers",
    "/livez/poststarthook/start-apiextensions-informers",
    "/livez/poststarthook/start-cluster-authentication-info-controller",
    "/livez/poststarthook/start-kube-aggregator-informers",
    "/livez/poststarthook/start-kube-apiserver-admission-initializer",
    "/logs",
    "/metrics",
    "/openapi/v2",
    "/readyz",
    "/readyz/autoregister-completion",
    "/readyz/etcd",
    "/readyz/log",
    "/readyz/ping",
    "/readyz/poststarthook/apiservice-openapi-controller",
    "/readyz/poststarthook/apiservice-registration-controller",
    "/readyz/poststarthook/apiservice-status-available-controller",
    "/readyz/poststarthook/bootstrap-controller",
    "/readyz/poststarthook/crd-informer-synced",
    "/readyz/poststarthook/generic-apiserver-start-informers",
    "/readyz/poststarthook/kube-apiserver-autoregistration",
    "/readyz/poststarthook/rbac/bootstrap-roles",
    "/readyz/poststarthook/scheduling/bootstrap-system-priority-classes",
    "/readyz/poststarthook/start-apiextensions-controllers",
    "/readyz/poststarthook/start-apiextensions-informers",
    "/readyz/poststarthook/start-cluster-authentication-info-controller",
    "/readyz/poststarthook/start-kube-aggregator-informers",
    "/readyz/poststarthook/start-kube-apiserver-admission-initializer",
    "/readyz/shutdown",
    "/version"
  ]
[[email protected] ~]#