3.2.7 Ensure that the --make-iptables-util-chains argument is set to true

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Information

Allow Kubelet to manage iptables.

Rationale:

Kubelets can automatically manage the required changes to iptables based on how you choose your networking options for the pods. It is recommended to let kubelets manage the changes to iptables. This ensures that the iptables configuration remains in sync with pods networking configuration. Manually configuring iptables with dynamic pod network configuration changes might hamper the communication between pods/containers and to the outside world. You might have iptables rules too restrictive or too open.

Impact:

Kubelet would manage the iptables on the system and keep it in sync. If you are using any other iptables management solution, then there might be some conflicts.

Solution

If using a Kubelet config file, edit the file to set makeIPTablesUtilChains: 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 remove the --make-iptables-util-chains argument from the KUBELET_SYSTEM_PODS_ARGS variable.
Based on your system, restart the kubelet service. For example:

systemctl daemon-reload
systemctl restart kubelet.service

Default Value:

See the GKE documentation for the default value.

See Also

https://workbench.cisecurity.org/files/4135