Free and Open Source Control Panels
Here are links and short discriptions of GNU/GPL/Apache-License hosting control panels, not all will run on core 4 without some serious mods (eg. they don't support core 4). It has been said the right strategy is to choose the OS to the control panel!
VHCS: Virtual Hosting Control System
From their site:
VHCS delivers a complete hosting automation appliance by offering significant security, total-cost-of-ownership, and performance advantages over competing commercial solutions.
With VHCS Pro you can configure your server and applications, create user with domains with a few point-and-click operations that take less than a minute. There is no limit to the number of resellers, users and domains that can be created.At the core of VHCS Pro are 3 easy-to-use, Web-based control panels. VHCS provides graphic user interfaces for the administrators, resellers and users.
Tested on: Fedora Core1, Core2 and Core 3 install instructions avbl for 4 as well
License: Mozilla Public License 1.1 (MPL 1.1)
Tested on: Fedora Core 1 - 4
License: BSD License
And old player on the GPL control panel market... http://www.web-cp.net/
web-cp is a full-featured, open source web hosting control panel written in PHP and released under the GPL. It consists of 4 control panels: personal, domain, reseller, and server. The personal control panel allows users to update their personal information, change their password and set their spam control settings. The domain control panel allows domain owners to add new users, aliases, subdomains, domain pointers and databases. The resellers control panel allows resellers to add or modify their domain accounts. The server control panel allows the server administrator to add or modify resellers, edit Virtual
Host and DNS templates, restart services and monitor server usage. Scripting, shell access, SSI, databases, mail, domains, etc are all controlled from a top-down approach. Web-CP.net is a continuation of the development of web://cp with it's ultimate goal being a 1.0 release. web-cp runs on almost every version of Unix/Linux/BSD and only Apache, MySQL and PHP are required.
Tested on: Core 1 and 2 (same install instruction page) It will probably run on the other cores as well
From their site:
ZPanel is a hosting control interface developed for both Windows and Linux hosts. We will soon be developing two different distributions to fit the needs of both platforms.
Tested on: Fedora 2
License: Freeware, artistic license, rumors it will go payware
Webmin is a web-based interface for system administration for Unix. Using any browser that supports tables and forms (and Java for the File Manager module), you can setup user accounts, Apache, DNS, file sharing and so on.
Webmin consists of a simple web server, and a number of CGI programs which directly update system files like /etc/inetd.conf and /etc/passwd. The web server and all CGI programs are written in Perl version 5, and use no non-standard Perl modules.
Tested on: a wide variaty of distributions, Fedora isn't mentioned, but falls under 'generic linux'
License: GNU GPL
SysCP, the System Control Panel is a server administration tool which enables an internet service provider to give their customers a web-based application to administrate their email addresses, their subdomains etc. The project was founded in autumn 2003 by Florian Lippert.
License: GNU GPL