What's the deal with Docker? - eviltoast

I never understood how to use Docker, what makes it so special? I would really like to use it on my Rapsberry Pi 3 Model B+ to ease the setup process of selfhosting different things.

I’m currently running these things without Docker:

  • Mumble server with a Discord bridge and a music bot
  • Maubot, a plugin-based Matrix bot
  • FTP server
  • Two Discord Music bots

All of these things are running as systemd services in the background. Should I change this? A lot of the things I’m hosting offer Docker images.

It would also be great if someone could give me a quick-start guide for Docker. Thanks in advance!