Ceph 3 upgrade guide and RHEL yum updates

In the Ceph 3 upgrade docs, there is no mention of when nor how it is safe to do a general yum update of the OS.

Presumably I can do a rolling yum -y update && reboot after an upgrade, but it's not clear if that is detrimental to ceph.

It is also unclear if yum update can be run at any time in the future without consideration given to updating ceph packages as a side effect.

In OpenShift there is an excluder package to ensure critical packages are only upgraded intentionally.