Luckily the S in USB stands for serial, so I have 3 printers connected to my server via USB and each one has its own octoprint docker container

As you've already noticed, the default way to get Octoprint running is by running it on an RPi with OctoPi as its operating system and connecting that to your printer using a serial connection, which basically means connecting a USB cable in your case.

The docker container gets interesting if your home server is physically close enough to your printer that you can connect the printer directly. Then you can just mount the serial connection into the container and run Octoprint there, cutting out the need for a RPi.

As others already said, the Prusa Mini also has PrusaLink integrated into its , which is an alternative to Octoprint and only needs the printer connected to your network via Ethernet or Wi-Fi with the Wi-Fi upgrade.

I'm getting mixed signals, (home server/seems like basics question). You just need to establish a TTY serial connection between the host and board. Linux is Linux regardless of the physical hardware.

Docker is just the new apt

Octoprint requires connecting printer to the computer running octoprint via a USB cable. It can be a raspberry pi but it doesn’t have to be.

The wifi dongle works with PrusaLink software which appears to be an alternative to Octoprint. So you’d use one or the other, not both together.

I guess you have some kind of linux based system of your home server. The USB connection to the printer will create a Serial Interface in your system under /dev. How it is called depends on the USB chip used in your printer, but often this is something like ttyUSB0.

So when connecting the printer you get the device file /dev/ttyUSB0 (or similar) on your home server (yes, the Serial interface is just a special file on that level). You can now mount this device file into the docker container like any other hostfile via the volume option.

Like docker run -v /dev/ttyUSB0:/dev/ttyUSB0 octoprint or by using the volumes key for your octoprint service in the docker-compose file, providing the same string as in the docker run command.

I think that should work, though I haven't tested it.

Besides what other people are mentioning it is also excellent to use docker if you want to run multiple instances for multiple printers. I currently run 3 printers on a single mini pc that is also running octofarm for having a single entry point for all my printers

If you're only using your computer for octoprint and it's a pi, you should probably just install octopI on the thing as its os. I run octoprint on a couple orange pi zero's, so I run it in docker. It also lets you easily use the computer for multiple things, and you can easily move your services from server to server with docker. Basically, unless you have a single use computer or something that makes docker rather difficult to use, docker is the way to go for hosting most things these days.

I used to use Octoprint to connect to an Ender 3, which didn't come with an internet connection. Now that I have an Ankermake M5, I don't use it anymore.

You could connect your desktop to the 3D printer, I don't think a Raspberry is required.