2.1.13 Ensure that the --rotate-certificates argument is not set to false

Information

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 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.

Note: This feature also require the RotateKubeletClientCertificate feature gate to be enabled (which is the default since Kubernetes v1.7)

Solution

If using a Kubelet config file, edit the file to add the line rotateCertificates: true.

If using command line arguments, edit the kubelet service file /etc/systemd/system/kubelet.service.d/10-kubeadm.conf on each worker node and add --rotate-certificates=true argument to the KUBELET_CERTIFICATE_ARGS variable. Based on your system, restart the kubelet service. For example:

systemctl daemon-reload
systemctl restart kubelet.service

Impact:

None

See Also

https://workbench.cisecurity.org/files/2125

Item Details

Category: CONFIGURATION MANAGEMENT

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

Plugin: Unix

Control ID: 5c90c35574b56bff96d11d7d33d57d07bfd051e5af6388858c283b706b05f32a