The kubelet server certificate rotation on controller-manager should be enabled
Set up the kubernetes integration.
Description
Enable kubelet server certificate rotation on controller-manager.
Rationale
RotateKubeletServerCertificate causes the kubelet to both request a serving certificate after bootstrapping its client credentials and rotate the certificate as its existing credentials expire. This automated periodic rotation ensures that the there are no downtimes due to expired certificates and thus addressing availability in the CIA security triad.
Note: This recommendation only applies if you let kubelets get their certificates from the API server. In case your kubelet certificates come from an outside authority/tool (e.g. Vault) then you need to take care of rotation yourself.
Audit
Run the following command on the master node:
ps -ef | grep kube-controller-manager
Verify that RotateKubeletServerCertificate argument exists and is set to true.
Edit the Controller Manager pod specification file /etc/kubernetes/manifests/kube-controller-manager.yaml on the master node and set the --feature-gates parameter to include RotateKubeletServerCertificate=true.
--feature-gates=RotateKubeletServerCe`rtificate=true
Impact
None
Default value
By default, RotateKubeletServerCertificate is not set.
References
- https://kubernetes.io/docs/admin/kubelet-tls-bootstrapping/#approval-controller
- https://github.com/kubernetes/features/issues/267
- https://github.com/kubernetes/kubernetes/pull/45059
- https://kubernetes.io/docs/admin/kube-controller-manager/
CIS controls
Version 6 14.2 Encrypt All Sensitive Information Over Less-trusted Networks All communication of sensitive information over less-trusted networks should be encrypted. Whenever information flows over a network with a lower trust level, the information should be encrypted.
Version 7 14.4 Encrypt All Sensitive Information in Transit Encrypt all sensitive information in transit.
