It turns out there are edge cases where the previous mechanism worked
and the new one doesn't. Employee subscription is one example, where the
key can be used to access basically any content, yet nothing it written
in the redhat.repo file. This should have no effect on hosts running
RHSM the usual way.
The problem: osbuild-composer used to have a rather uncomplete logic for
selecting client certificates and keys while fetching data from
repositories that use the "subscription model". In this scenario, every
repo requires the user to use a client-side TLS certificate. The problem
is that every repo can use its own CA and require a different pair of
a certificate and a key. This case wasn't handled at all in composer.
Furthermore, osbuild-composer can use remote workers which complicates
things even more.
Assumptions: The problem outlined above is hard to solve in the general
case, but Red Hat Subscription Manager places certain limitations on how
subscriptions might be used. For example, a subscription must be tight to
a host system, so there is no way to use such a repository in osbuild-composer
without it being available on the host system as well.
Also, if a user wishes to use a certain repository in osbuild-composer it
must be available on both hosts: the composer and the worker. It will come
with different pair of a client certificate and a key but otherwise, its
configuration remains the same.
The solution: Expect all the subscriptions to be registered in the
/etc/yum.repos.d/redhat.repo file. Read the mapping of URLs to certificates
and keys from there and use it. Don't change the manifest format and let
osbuild guess the appropriate subscription to use.
