Red Hat Bugzilla – Bug 1317023
SELinux prevents mounted ca.crt and token from being read in a Kubernetes pod
Last modified: 2018-06-01 06:35:02 EDT
Description of problem: A correctly configured kubernetes will mount a ca.crt and token data into pods at their path: /var/run/secrets/kubernetes.io/serviceaccount/ However SELinux on the node prevents access to the ca.crt and token files. Turning off SELinux (setenforce 0) allows access again. Version-Release number of selected component (if applicable): kubernetes-1.1.0-0.17.git388061f.fc23.x86_64 How reproducible: Every time.
Created attachment 1135317 [details] Script to setup kubernetes Kubernetes as packaged in Fedora requires a scripted setup before it is able to start pods appropriately. This file is part of reproducing this issue, it should be run before kubernetes services are started.
Created attachment 1135318 [details] A simple pod to reproduce the issue
Make sure SELinux is enforcing: # setenforce 1 First setup and start kubernetes: # wget -o kubernetes.setup https://bugzilla.redhat.com/attachment.cgi?id=1135317 # sh kubernetes.setup # systemctl start docker etcd kube-apiserver kube-controller-manager kube-scheduler kubelet kube-proxy Now deploy a pod to the new kubernetes cluster: # wget -o pod.json https://bugzilla.redhat.com/attachment.cgi?id=1135318 # kubectl create -f pod.json Wait for the pod to start: # kubectl get pods Now log into the pod and try to access the mounted secrets: # kubectl exec -ti tiny /bin/cat /var/run/secrets/kubernetes.io/serviceaccount/ca.crt Actual results: # kubectl exec -ti tiny /bin/cat /var/run/secrets/kubernetes.io/serviceaccount/ca.crt cat: can't open '/var/run/secrets/kubernetes.io/serviceaccount/ca.crt': Permission denied error: Error executing remote command: Error executing command in container: Error executing in Docker Container: 1 Expected results (which you can see if you setenforce 0): # kubectl exec -ti tiny /bin/cat /var/run/secrets/kubernetes.io/serviceaccount/ca.crt -----BEGIN CERTIFICATE----- MIIC/TCCAeWgAwIBAgIJAJBPiGTbKtEeMA0GCSqGSIb3DQEBCwUAMBUxEzARBgNV BAMMCmt1YmVybmV0ZXMwHhcNMTYwMzExMTc0MDQ0WhcNMjQwODA4MTc0MDQ0WjAV MRMwEQYDVQQDDAprdWJlcm5ldGVzMIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIB CgKCAQEA20PGPb5EPdf76bFO5/jdbIER6wlQsuERqCi7B50KtoxM41JF1RcmRX1W ...
Paul, haven't we talked about this like 1bazillion times? We need to label /var/lib/kubelet/something differently?
Are these specific to each pod, or do they need to be shared between all pods?
> Are these specific to each pod, or do they need to be shared between all pods? The CA is shared between all pods. I believe the token file is specific to the pods serviceaccount configuration.
Then they should be mounted shared.
/var/lib/kubelet needs to be labeled with svirt_sandbox_file_t for mounts like this to work correctly. I notice this issue is still open from March -- is this still an issue?
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