Linux§
Several distributions are fit for self-hosting. The final choice will depend on your needs.
Yunohost§
Yunohost is probably the easiest linux distribution to self-host software. It provides administrators with a web-interface, and packaged applications can usually be installed very qyuickly. Yunohost is based on Debian.
Yunohost doesn't support officially Docker yet.
You can still install manually docker and run containers.
Other Linux distributions...§
If you do not wish to use Yunohost, you can use any other Linux distribution. They may be harder to install and configure, but you may be able to tune it more finally.
BSD§
BSD is another UNIX OS. However, it is less used than Linux, but one could use it for self-hosting.
Windows§
If you have any tips about using Windows for hosting web applications, feel free to share them !