Ensure that the --rotate-certificates argument is not present or is set to true

Description:

Enable kubelet client certificate rotation.

Rationale:

The '--rotate-certificates' setting causes the kubelet to rotate its client certificates by creating new CSRs as its existing credentials expire. This automated periodic rotation ensures that the there is no downtime due to expired certificates and thus addressing availability in the CIA (Confidentiality, Integrity, and Availability) 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 implement rotation yourself.

Note: This feature also requires the 'RotateKubeletClientCertificate' feature gate to be enabled.

None

Remediation Method 1:

If modifying the Kubelet config file, edit the kubelet-config.json file '/etc/kubernetes/kubelet/kubelet-config.json' and set the below parameter to true

"RotateCertificate":true

Additionally, ensure that the kubelet service file /etc/systemd/system/kubelet.service.d/10-kubelet-args.conf does not set the --RotateCertificate executable argument to false because this would override the Kubelet config file.

Remediation Method 2:

If using executable arguments, edit the kubelet service file '/etc/systemd/system/kubelet.service.d/10-kubelet-args.conf' on each worker node and add the below parameter at the end of the 'KUBELET_ARGS' variable string.

--RotateCertificate=true