1.3.6 Ensure that the RotateKubeletServerCertificate argument is set to true

Information

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.

Solution

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=RotateKubeletServerCertificate=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/

See Also

https://workbench.cisecurity.org/files/2662

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-3(6), CSCv6|14.2, CSCv7|14.4

Plugin: Unix

Control ID: 5a9bfa11f1b0354cfeb7478e48718a1a74737b3eff9aef5d641307346c05c6f3