通过serviceAccount的secret访问kubernetes API Server

た入场券 2023-07-22 09:22 13阅读 0赞

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。  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3J1c3NsZQ_size_16_color_FFFFFF_t_70]

# 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

curl -s $APISERVER/api/v1/namespaces/default/pods/ --header "Authorization: Bearer $TOKEN" --cacert /tmp/ca.crt | jq -rM '.items[].metadata.name'

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3J1c3NsZQ_size_16_color_FFFFFF_t_70 1]

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  
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# 额外部分 #

jq获取secret  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3J1c3NsZQ_size_16_color_FFFFFF_t_70 3]

jq获取从secret获取token  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3J1c3NsZQ_size_16_color_FFFFFF_t_70 4]

jq从secret获取ca证书  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3J1c3NsZQ_size_16_color_FFFFFF_t_70 5]

[root@node1 ~]# 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"
      ]
    [root@node1 ~]#

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