Manage Existing Servers with Katello



I would like to know how can I add existing servers in my network to be managed by Katello with the same exact capabilities as though I provisioned a new server using Katello.

I have tried running ansible playbook

 - hosts: all
   - setup:

and although it allowed hosts to be recognised by Katello but puppet does not obtain regular fact reports from the hosts. Furthermore I am also unable to run the ansible roles that are attached to my hostgroups

Other relevant data:
In short, how can I register my existing servers to be managed by katello fully.