After a bit of struggle, I managed to setup a USB passthrough for my 3D printer from my Proxmox host to a Ubuntu container that runs Repetier Host. The printer is set as /dev/ttyUSB0. Everything works fine so long as the container is freshly rebooted. However, if after a couple of hours I turn the printer back on to run another job it is shown as disconnected. When I check the output from ls -al /dev on the container, ttyUSB0 is still there but has lost the correct file permissions and group; it's now at 000 instead of 660, and no longer has the dialout group set. If I reboot the container and run ls -al /dev again everything is back to normal and the printer connects and works fine. I had the sense that this might be an issue with the USB port going to "sleep," however I haven't been able to find anything online that has addressed how to resolve that in a container - most posts reference laptop-mode, etc, which I don't have on the container. I'd appreciate any insight. It'd certainly be much better if I didn't have to login to Proxmox and reboot the container every time I want to print!