Description of the problem:

I have enabled the following repositories and initiated a bulk sync:

Red Hat Enterprise Linux 8 for x86_64 - AppStream RPMs 8

Red Hat Enterprise Linux 8 for x86_64 - BaseOS RPMs 8

Red Hat Satellite Client 6 for RHEL 8 x86_64 RPMs

However, "Red Hat Enterprise Linux 8 for x86_64 - AppStream RPMs 8" failed with the following error message:

~~~
PG::ForeignKeyViolation: ERROR: insert or update on table "katello_module_stream_rpms" violates foreign key constraint "katello_msrpm_rpm_id_fk"
DETAIL: Key (rpm_id)=(116782) is not present in table "katello_rpms".
~~~

Re-synchronizing 'Red Hat Enterprise Linux 8 for x86_64 - AppStream RPMs 8' resolved the issue.