Heads-up for Satellite 6.4 to 6.5 update (Error 500 when querying virt-who hosts - undefined method `split' for nil:NilClass)

[kallies]

katello-attach-subscription wasn't working properly after we updated Satellite from 6.4 to 6.5. Running katello-attach-subscription with the --verbose parameter revealed, that some virt-who hosts are returning Error 500. This was reproducible in UI, API and hammer:

hammer host info --name virt-who-node.fqdn-1
{
  "error": {"message":"undefined method `split' for nil:NilClass"}
}

There is a bugzilla and a solution article about this issue.

Another way is to add an additional interface, set to primary, managed and remove the old one - which is a bit annoying if there are a lot of hosts.