首页 > 其他分享> > Kubernetes CKS 2021 Complete Course + Simulator笔记【9】---Exercise caution in using ServiceAccounts
Kubernetes CKS 2021 Complete Course + Simulator笔记【9】---Exercise caution in using ServiceAccounts
作者：互联网
文章目录
1. 介绍
2. Practice - Pod uses custom ServiceAccount
root@master:~/cks/RBAC# k get sa,secrets
NAME SECRETS AGE
serviceaccount/default 1 9m50s
NAME TYPE DATA AGE
secret/default-token-9srgx kubernetes.io/service-account-token 3 9m50s
root@master:~/cks/RBAC# k describe sa default
Name: default
Namespace: default
Labels: <none>
Annotations: <none>
Image pull secrets: <none>
Mountable secrets: default-token-9srgx
Tokens: default-token-9srgx
Events: <none>
root@master:~/cks/RBAC# k create sa accessor
serviceaccount/accessor created
root@master:~/cks/RBAC# k get sa,secrets
NAME SECRETS AGE
serviceaccount/accessor 1 5s
serviceaccount/default 1 17m
NAME TYPE DATA AGE
secret/accessor-token-bnd4s kubernetes.io/service-account-token 3 5s
secret/default-token-9srgx kubernetes.io/service-account-token 3 17m
root@master:~/cks/RBAC# k describe secret accessor-token-bnd4s
Name: accessor-token-bnd4s
Namespace: default
Labels: <none>
Annotations: kubernetes.io/service-account.name: accessor
kubernetes.io/service-account.uid: 9e763e70-71da-431a-a813-df838420341b
Type: kubernetes.io/service-account-token
Data
====
ca.crt: 1066 bytes
namespace: 7 bytes
token: eyJhbGciOiJSUzI1NiIsImtpZCI6IkJhb1NtQ21TRlpKWHBYbUV3VHZ6OW9FOFZoOV9BSlNrLUN1WEJ4SjZtc1EifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZWNyZXQubmFtZSI6ImFjY2Vzc29yLXRva2VuLWJuZDRzIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFjY2Vzc29yIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiOWU3NjNlNzAtNzFkYS00MzFhLWE4MTMtZGY4Mzg0MjAzNDFiIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50OmRlZmF1bHQ6YWNjZXNzb3IifQ.lAy_-h3rMcZSNHtwm2THelbj-2O635N75Hx92-4t9Ulaplk0WOg9Ja72LlReasU39VS1DMAwYfgNgsyurDme2HVolO4IEeyl56BrOgKC73LWLQ1d6waNqPVzU_GRKuzXqpDXJID3CODcuNBOld1VHyIbmK2YNzgPMaR0CLexpx_p_wU5mg_XZpfccL4KvFBNmWh_cj3eFz4t1yxsP2TycwC2WKkXMvpaVqY_YFFpge2ddTwBf-xgtcpoRAQpfEkxZSVWqA12ZTi0I2wdK--XMcJcqmTTor1rcAws_aLUxT7VajL4sgd4LT_OuJk4iQdLmQZzwDYS4-Ca354pNIK0PA
root@master:~/cks/RBAC# k run accessor --image=nginx --dry-run=client -oyaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: accessor
name: accessor
spec:
containers:
- image: nginx
name: accessor
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
root@master:~/cks/RBAC# k run accessor --image=nginx --dry-run=client -oyaml > accessor.yaml
root@master:~/cks/RBAC# vim accessor.yaml
root@master:~/cks/RBAC# cat accessor.yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: accessor
name: accessor
spec:
serviceAccountName: accessor #添加此行
containers:
- image: nginx
name: accessor
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
root@master:~/cks/RBAC# k create -f accessor.yaml
pod/accessor created
root@master:~/cks/RBAC# k exec -ti accessor -- bash
root@accessor:/# mount |grep sec
tmpfs on /run/secrets/kubernetes.io/serviceaccount type tmpfs (ro,relatime)
root@accessor:/# cd /run/secrets/kubernetes.io/serviceaccount
root@accessor:/run/secrets/kubernetes.io/serviceaccount# cat token
eyJhbGciOiJSUzI1NiIsImtpZCI6IkJhb1NtQ21TRlpKWHBYbUV3VHZ6OW9FOFZoOV9BSlNrLUN1WEJ4SjZtc1EifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZWNyZXQubmFtZSI6ImFjY2Vzc29yLXRva2VuLWJuZDRzIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFjY2Vzc29yIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiOWU3NjNlNzAtNzFkYS00MzFhLWE4MTMtZGY4Mzg0MjAzNDFiIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50OmRlZmF1bHQ6YWNjZXNzb3IifQ.lAy_-h3rMcZSNHtwm2THelbj-2O635N75Hx92-4t9Ulaplk0WOg9Ja72LlReasU39VS1DMAwYfgNgsyurDme2HVolO4IEeyl56BrOgKC73LWLQ1d6waNqPVzU_GRKuzXqpDXJID3CODcuNBOld1VHyIbmK2YNzgPMaR0CLexpx_p_wU5mg_XZpfccL4KvFBNmWh_cj3eFz4t1yxsP2TycwC2WKkXMvpaVqY_YFFpge2ddTwBf-xgtcpoRAQpfEkxZSVWqA12ZTi0I2wdK--XMcJcqmTTor1rcAws_aLUxT7VajL4sgd4LT_OuJk4iQdLmQZzwDYS4-Ca354pNIK0PA
tes.io/serviceaccount# curl https://kubernetes
curl: (60) SSL certificate problem: unable to get local issuer certificate
More details here: https://curl.haxx.se/docs/sslcerts.html
curl failed to verify the legitimacy of the server and therefore could not
establish a secure connection to it. To learn more about this situation and
how to fix it, please visit the web page mentioned above.
root@accessor:/run/secrets/kubernetes.io/serviceaccount# curl https://kubernetes -k
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:anonymous\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
}
#以serviceaccount用户accessor访问
root@accessor:/run/secrets/kubernetes.io/serviceaccount# curl https://kubernetes -k -H "Authorization: Bearer eyJhbGciOiJSUzI1NiIsImtZCI6IkJhb1NtQ21TRlpKWHBYbUV3VHZ6OW9FOFZoOV9BSlNrLUN1WEJ4SjZtc1EifQ.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJkZWZhdWx0Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZWNyZXQubmFtZSI6ImFjY2Vzc29yLXRva2VuLWJuZDRzIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQubmFtZSI6ImFjY2Vzc29yIiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9zZXJ2aWNlLWFjY291bnQudWlkIjoiOWU3NjNlNzAtNzFkYS00MzFhLWE4MTMtZGY4Mzg0MjAzNDFiIiwic3ViIjoic3lzdGVtOnNlcnZpY2VhY2NvdW50OmRlZmF1bHQ6YWNjZXNzb3IifQ.lAy_-h3rMcZSNHtwm2THelbj-2O635N75Hx92-4t9Ulaplk0WOg9Ja72LlReasU39VS1DMAwYfgNgsyurDme2HVolO4IEeyl56BrOgKC73LWLQ1d6waNqPVzU_GRKuzXqpDXJID3CODcuNBOld1VHyIbmK2YNzgPMaR0CLexpx_p_wU5mg_XZpfccL4KvFBNmWh_cj3eFz4t1yxsP2TycwC2WKkXMvpaVqY_YFFpge2ddTwBf-xgtcpoRAQpfEkxZSVWqA12ZTi0I2wdK--XMcJcqmTTor1rcAws_aLUxT7VajL4sgd4LT_OuJk4iQdLmQZzwDYS4-Ca354pNIK0PA"
{
"kind": "Status",
"apiVersion": "v1",
"metadata": {
},
"status": "Failure",
"message": "forbidden: User \"system:serviceaccount:default:accessor\" cannot get path \"/\"",
"reason": "Forbidden",
"details": {
},
"code": 403
3. Practice - Disable ServiceAccount mounting
参考链接：
https://kubernetes.io/docs/tasks/configure-pod-container/configure-service-account/
root@master:~/cks/serviceaccount# vim accessor.yaml
root@master:~/cks/serviceaccount# cat accessor.yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: accessor
name: accessor
spec:
serviceAccountName: accessor
automountServiceAccountToken: false #添加此行
containers:
- image: nginx
name: accessor
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
root@master:~/cks/serviceaccount# k -f accessor.yaml replace --force
pod "accessor" deleted
pod/accessor replaced
root@master:~/cks/serviceaccount# k get pods
NAME READY STATUS RESTARTS AGE
accessor 1/1 Running 0 13s
root@master:~/cks/serviceaccount# k exec -ti accessor -- bash
root@accessor:/# mount |grep ser
root@master:~/cks/serviceaccount# vim accessor.yaml
apiVersion: v1
kind: Pod
metadata:
creationTimestamp: null
labels:
run: accessor
name: accessor
spec:
serviceAccountName: accessor
automountServiceAccountToken: true #false改为true
containers:
- image: nginx
name: accessor
resources: {}
dnsPolicy: ClusterFirst
restartPolicy: Always
status: {}
#pod文件含挂载的token
root@master:~/cks/serviceaccount# k edit pod accessor
.....
volumeMounts:
- mountPath: /var/run/secrets/kubernetes.io/serviceaccount
name: accessor-token-bnd4s
readOnly: true
.....
volumes:
- name: accessor-token-bnd4s
secret:
defaultMode: 420
secretName: accessor-token-bnd4s
.....
4. Practice - Limit ServiceAccounts using RBAC
root@master:~/cks/serviceaccount# k get pod
NAME READY STATUS RESTARTS AGE
accessor 1/1 Running 0 5m2s
root@master:~/cks/serviceaccount# k auth can-i delete secrets --as system:serviceaccount:default:accessor
no
root@master:~/cks/serviceaccount# k create clusterrolebinding accessor --clusterrole edit --serviceaccount default:accessor
clusterrolebinding.rbac.authorization.k8s.io/accessr created
root@master:~/cks/serviceaccount# k auth can-i delete secrets --as system:serviceaccount:default:accessor
yes
总结
标签：Complete,Kubernetes,Simulator,serviceaccount,token,master,cks,root,accessor 来源： https://blog.csdn.net/xixihahalelehehe/article/details/116133701