4.2.6 Ensure that the --protect-kernel-defaults argument is set to true

Information

Protect tuned kernel parameters from overriding kubelet default kernel parameter values.

Rationale:

Kernel parameters are usually tuned and hardened by the system administrators before putting the systems into production. These parameters protect the kernel and the system. Your kubelet kernel defaults that rely on such parameters should be appropriately set to match the desired secured system state. Ignoring this could potentially lead to running pods with undesired kernel behavior.

Impact:

You would have to re-tune kernel parameters to match kubelet parameters.

Solution

If using a Kubelet config file, edit the file to set protectKernelDefaults: true.
If using command line arguments, edit the kubelet service file /etc/kubernetes/kubelet.conf on each worker node and set the below parameter in KUBELET_SYSTEM_PODS_ARGS variable.

--protect-kernel-defaults=true

Based on your system, restart the kubelet service. For example:

systemctl daemon-reload
systemctl restart kubelet.service

Default Value:

By default, --protect-kernel-defaults is not set.

See Also

https://workbench.cisecurity.org/files/3892

Item Details

Category: CONFIGURATION MANAGEMENT

References: 800-53|CM-6, 800-53|CM-7, CSCv7|5.2

Plugin: Unix

Control ID: 40bb868ed05eec4b1220961d9d60031b90fd44e0563c03cc3fff4237d08d47a0