The section "About RHCOS image layering"[1] says as follows in "Machine configuration" guide:

> About RHCOS image layering
> Image layering allows you to customize the underlying node operating system on any of your cluster worker nodes. This helps keep everything up-to-date, including the node operating system and any added customizations such as specialized software.

According to the documentation, customisation is limited to "worker" nodes only. Is this a correct description?
I think that all nodes (including "control plane" nodes and "infra" nodes) can also be customised.

[1] https://docs.openshift.com/container-platform/4.17/machine_configuration/mco-coreos-layering.html#coreos-layering-about_mco-coreos-layering

    4.17.0

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