If you can afford it, cPanel is probably the best hosting control panel on the market. It is a complete solution for Linux hosting automation. If you cannot afford the commercial licensing, just need a control panel for a dev or testing environment, or want something with a more permissive license, you might want to explore some of these free and open source alternative control panels.
Webmin – One of the oldest solutions on the block, Webmin runs on a variety of operating systems and gives you complete system administrative control. Its sub components, Virtualmin, Usermin and Cloudmin add further functionality.
ISPConfig – Designed to be stable and secure, ISPConfig can manage one or many servers. It supports a number of Linux distributions and also several software options for web server, database server, etc.
OpenPanel – Also for Linux servers, OpenPanel is a modular control panel that features both graphical and command line interfaces for Linux servers.
Zpanel – Written in PHP, Zpanel is light and flexible, working on Windows, Linux and other Unix-like operating systems. It supports modules, themes and more.
Ajenti – A relative newcomer, Ajenti sports a modern interface and a number flexible features, such as support for Nginx and Apache web servers. It can serve as a server management panel and also a hosting panel with the hosting add-on.
Free and open source control panels can be just as powerful and feature-rich as proprietary ones. What they generally lack, however, is commercial support or any kind of warranty. Some developers offer additional paid commercial support, while others offers support through community forums and discussion groups.