The best open source alternative to Turnkey Linux is Cloudron, which is both free and Open Source. If that doesn't suit you, our users have ranked more than 10 alternatives to Turnkey Linux and six of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Turnkey Linux are BitNami Application Stacks (Free, Open Source), Zentyal (Paid, Open Source), Univention Corporate Server (Free, Open Source) and Virtual Machines (Free, Open Source).
Cloudron is a complete solution for managing apps & users on your own server. Easily deploy production ready apps from the app library and keep them automatically up-to-date. It even comes with a built-in email server and web clients!.
BitNami Stacks make it incredibly easy to deploy your favorite open source software. BitNami Stacks include an open source application and all of the other software necessary to run it, such as Apache, MySQL, PHP or Ruby.
Zentyal is a native Microsoft Active Directory implementation on Linux incorporating all the network services required in a small and medium business environment: Directory & Domain Server, Mail Server, Gateway and Infrastructure Server.
The idea is to simplify developers configuration work through lightweight and powerful environments in order to help them to devote more time to their passion: the code. Moreover, it can be interesting for Linux and virtualisation enthusiasts.
Linux based gateway for SMB with accent on security. With easy to use web-based configuration tool. With lots of additional features like mail server, VPN server, traffic shaping, DPI, traffic antivirus and etc.