Initially we were considering Red Hat Satellite for applying patches to all our Linux Physical as well as Virtual Servers. Our client didn't wanted to pay for the licensing cost and then we decided to go with Katello/Foreman. It's an open source complete life cycle systems management tool for provisioning, configuring and monitoring of physical and virtual servers. We didn't had any technical background knowledge of using Katello. The setup was easy and pushing patches to servers is also very convenient. Katello is essentially Foreman Plug-in for Subscription and Repository Management. and also facilitates provisioning and life cycle management through Foreman.