Description of problem

Since nodeDisruptionPolicy GAed in 4.17, our docs have said:

There are machine configuration changes that always require a reboot, regardless of any node disruption policies. For more information, see About the Machine Config Operator.

and the referenced section says:

• When the MCO detects changes to the /etc/containers/registries.conf file, such as editing an ImageDigestMirrorSet, ImageTagMirrorSet, or ImageContentSourcePolicy object, it drains the corresponding nodes, applies the changes, and uncordons the nodes. The node drain does not happen for the following changes:
  • The addition of a registry with the pull-from-mirror = "digest-only" parameter set for each mirror.
  • The addition of a mirror with the pull-from-mirror = "digest-only" parameter set in a registry.
  • The addition of items to the unqualified-search-registries list.

However, setting nodeDisruptionPolicy in the cluster MachineConfiguration can set the policy on ImageContentSourcePolicy removal, and the documentation should be clarified to reflect that.

Version-Release number of selected component

The current wording exists in both 4.17 and 4.20

How reproducible

Every time.

Steps to Reproduce

Read the nodeDisruptionPolicy docs.

Actual results

The impression that ImageContentSourcePolicy removal might require its usual drain/reload, regardless of the nodeDisruptionPolicy configuration.

Expected results

A clearer description of the situations that nodeDisruptionPolicy cannot configure, or the removal of the "There are machine configuration changes that always require a reboot, regardless of any node disruption policies" note.