Cannot forward USB device to Proxmox LXC as it changes ID every time it is unplugged

Question

I am setting up a printer in a Debian LXC image on Proxmox. I identified the printer in lsusb:

Bus 001 Device 007: ID 04f9:01ea Brother Industries, Ltd DCP-7030

and I forward it in Proxmox (device /dev/bus/usb/001/007).

As soon as I unplug the printer and plug it back in, it always gets a new ID, for example:

Bus 001 Device 005: ID 04f9:01ea Brother Industries, Ltd DCP-7030

The printer does not show up in /dev/serial/*.

There are three possible solutions I can think of:

Somehow fix the ID, such that I can forward it statically
Forward all USB devices
Reference the printer as a symlink (udev rule TTRS{idVendor}=="04f9", ATTRS{idProduct}=="01ea", SYMLINK+="brother_printer" works, but CUPS/SANE are unable to detect it as a printer)

I am unsure which of these is the most promising path and how to proceed with it.

The ID is 04f9:01ea, and isn't changing. The "Bus" (001), is which USB host device you connected it to. The "Device" is a connection specific entry of how the system internally refers to this device. It is expected to change, and can't be fixed. You might be able to put the forwarding into a udev rule, or write a script to parse the output if lsusb -d 04f9:01ea. You might be able to forward it by 04f9:01ea (though maybe not as there could be two matching devices). — David G.
– David G., Commented Oct 13, 2024 at 19:39
@DavidG. Thanks, that's a good idea. I see this option for VMs but not for LXC containers. Do you know how forwarding by VendorID/DeviceID works for containers? — Post Self
– Post Self, Commented Oct 14, 2024 at 6:54
Sorry, can't specifically help you there, but: The LXC container's filesystem may be in your parent filesystem, allowing udev to write into it. Mind you, a symlink probably wouldn't work as the container couldn't see the target Instead you would need to make a device node. — David G.
– David G., Commented Oct 14, 2024 at 7:00
@DavidG. Ok, I switched the entire system from LXC to a VM and now it all works great. Thanks for the hint — Post Self
– Post Self, Commented Oct 14, 2024 at 8:01

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