(R)?ex is described as '- manage all your boxes from a central point - Datacenter Automation and Configuration Management' and is an app in the Development category. There are more than 25 alternatives to (R)?ex for a variety of platforms, including Linux, Mac, Windows, Online / Web-based and BSD. The best alternative is Ansible, which is both free and Open Source. Other great apps like (R)?ex are Salt (Free, Open Source), Puppet (Freemium, Open Source), Chef (Free, Open Source) and Foreman (Free, Open Source).
Chef is an open source systems integration framework built to bring the benefits of configuration management to your entire infrastructure. You write source code to describe how you want each part of your infrastructure to be built, then apply those descriptions to your servers.
Ensure compliance Define the desired state and configuration of your IT infrastructure, and CFEngine will automatically ensure that it complies. Automate Automatically roll out updates and changes to every node in your infrastructure, whether you have 50 or 50,000 nodes.