The issue here is I would be going from centos 7 to centos 8 stream, so I really don’t want to upgrade both foreman/katello AND the OS at the same time.
I may try to advance the old foreman/katello to a version that is supported in both centos 7 and centos8 stream, THEN try to backup and restore between…
you can only import backups into the same version the backup was taken on.
So, backing up on a Foreman 3.2 and restoring to another 3.2 should work (some limitations may apply, idk), but taking a backup from say 2.4 and restoring that to 3.5 will not work.
I myself have done the EL7 → EL8 upgrade on Foreman 3.2 (which supports both) and upgraded in-place via LEAPP. That might be the easier solution, depending on what version of Foreman you are coming from and how many clients you are managing. There is also documentation how to do that available here. That has worked quite well for me after figuring out how to handle some quirks specific to our organization. Still I would advise for the usual precautions like taking a full-backup or snapshot of your system beforehand.
I really appreciate that. knowing I can restore to the same version of foreman regardless of the underlying OS helps.
having said that, I have already had to completely rebuild forman and start from scratch on the contentviews so that’s not going to be that big a problem, though that’s helped by the fact we don’t have too many inter-dependencies.