[SOLVED] Pass USB Device to LXC

[xadox]

Hello All.
I am on Proxmox V7.3-6. And I want to pass a USB Device on an unprivileged Ubuntu20.04.5 LTS LXC.
The USB device is a USB adapter to read my SmartMeter:

root@proxmox:~# lsusb Bus 003 Device 002: ID 10c4:ea60 Silicon Labs CP210x UART Bridge

I followed several instructions on the net. Unfortunately this does not work properly.
The most promising seems to be this tutorial:

https://www.schreiners-it.de/proxmox/usb-geraet-in-lxc-container-unter-proxmox-7-1/

But it starts directly with the fact that no ttyACM0 is created for me. I only have ttyUSB0.
ttyUSB0 is always present regardless of whether the following command is used in one of the LXC configs:

lxc.mount.entry: /dev/bus/usb/003/006 dev/bus/usb/ none bind,optional,create=file

Then sometimes lxc.cgroup2.devices.allow is used and sometimes lxc.cgroup.devices.allow.

Any tips would be greatly appreciated.

 

[Max Carrara]

Hmm, have you tried create=dir instead of create=file already? My gut tells me create=file should be correct, but it's worth a try nevertheless.

Another thing I have noticed: Why is there a trailing / in dev/bus/usb/? Skimming the LXC docs, I can't really find anything regarding the actual path specification, so I'm not sure a trailing slash actually makes a difference or not; but maybe try something like dev/bus/usb/003/006 instead. Just for good measure.

So, the full mount entries I'd suggest you try are:

1.
lxc.mount.entry: /dev/bus/usb/003/006 dev/bus/usb/003/006 none bind,optional,create=file

2.
lxc.mount.entry: /dev/bus/usb/003/006 dev/bus/usb/003/006 none bind,optional,create=dir

Also, make sure your device has the required permissions by doing a chmod a+rw /dev/bus/usd/003/006 beforehand.

 

[xadox]

I have tested a bit more. You are totaly right.
The command should be without the ending "/":

lxc.cgroup2.devices.allow: c 189:* rwm lxc.mount.entry: /dev/bus/usb/003/002 dev/bus/usb none bind,optional,create=file

The first "/dev/bus/usb/003/002" is the mount point on the host. The Second one "dev/bus/usb" is the mount target on the lxc.
This creates the file "dev/bus/usb" on the lxc.

root@iob:/dev/bus# ls -la crw-rw-rw- 1 nobody nogroup 189, 257 Mar 14 14:51 usb

Thats working. But if I read the tutorials correctly there should be now a ttyACM0 device created on the host.
And for me thats not working. Instead I am using dev/ttyUSB0:

lxc.cgroup2.devices.allow: c 188:* rwm lxc.mount.entry: /dev/ttyUSB0 dev/ttyUSB0 none bind,optional,create=file

And with that I am able to use the USB device in the lxc.

 

[malte669966]

The Same worked with me.
Unfortunately when I Hotswap the USB Device. I loose the connection an the rights.
I receive: ls -al /dev/ttyUSB0
c--------- 0 nobody nogroup 188, 0 Aug 6 19:58 /dev/ttyUSB0

one I restart the LXC, everything is working again.

Anyone an Idea how to get the permissions Hotswap-compatible?

Rgds
Malte

 

[GleraK]

The Same worked with me.
Unfortunately when I Hotswap the USB Device. I loose the connection an the rights.
I receive: ls -al /dev/ttyUSB0
c--------- 0 nobody nogroup 188, 0 Aug 6 19:58 /dev/ttyUSB0

one I restart the LXC, everything is working again.

Anyone an Idea how to get the permissions Hotswap-compatible?

Rgds
Malte

Hi all.
I have the same problem afrter re-plug device (in 8.1.10). Is there any progress? Some settings or workaround?
Thx

 

[leesteken]

Some settings or workaround?

Work-around: add a udev rule to reboot the container on the USB plug-in event?

 

[CycloneB]

Work-around: add a udev rule to reboot the container on the USB plug-in event?

I've hit a similar snag (though in my case I don't need to reboot the container, I need to reset the permissions every time the device is plugged back in). Could you point me to guide on how you write such a udev rule? I have that creates a symlink to a permanent name, but I've not had luck finding a writeup on how you would do other commands via the rule.

 

[mrexodia]

Today I managed to get my USB smart card (ACR39U) to work in an unprivileged LXC container. My lsusb output was:

Bus 001 Device 007: ID 072f:b100 Advanced Card Systems, Ltd ACR39U

First I added the device /dev/bus/usb/001/007 to the container in the web UI and everything worked. Unfortunately on reboot/replug the ID changed, so I followed leesteken's suggestion to add a udev rule. I created /etc/udev/rules.d/10-local.rules with the following contents:

ACTION=="add", SUBSYSTEM=="usb", ATTRS{idVendor}=="072f", ATTRS{idProduct}=="b100", ENV{DEVNAME}!="", RUN+="/etc/udev/rules.d/smartcard.sh $devnode"

The smartcard.sh script looks like this:

#!/bin/bash
cd "$(dirname "$0")"

echo "[$(date)] smart card add" >> smartcard.log

CONTAINER_ID=103
CONFIG_FILE=/etc/pve/lxc/$CONTAINER_ID.conf

# Extract the current path from the config file
CURRENT_PATH=$(grep '^dev0:' "$CONFIG_FILE" | awk -F': ' '{print $2}')

# Compare the extracted path with $DEVNAME
if [ "$CURRENT_PATH" != "$1" ]; then
  # Replace the path in the config file
  sed -i "s|^dev0: .*|dev0: $1|" "$CONFIG_FILE"
  echo "Updated dev0 path in $CONFIG_FILE from $CURRENT_PATH to $1." >> smartcard.log
  CONTAINER_STATE=$(lxc-info --name $CONTAINER_ID --state --no-humanize)
  if [ "$CONTAINER_STATE" != "RUNNING" ]; then
    nohup lxc-start --name $CONTAINER_ID >> smartcard.log 2>&1 &
  else
    nohup lxc-stop --name $CONTAINER_ID --reboot >> smartcard.log 2>&1 &
  fi
else
  echo "The dev0 path is already set to $1" >> smartcard.log
fi

You can reload the rules without reboot using: udevadm control --reload-rules

 

[martin-g-it]

Why not mount the device via serial id? This won't change upon reboot/replug..
ls -l /dev/serial/by-id to get the ID.

 

[mrexodia]

Why not mount the device via serial id? This won't change upon reboot/replug..
ls -l /dev/serial/by-id to get the ID.

On my Proxmox host this folder does not exist. I tried creating a symbolic link using udev rules and the device showed up in the container when running lsusb. However, the smart card driver did not recognize it and I was unable to connect to it. Passing the /dev/usb/ device worked, so I just powered through and got it to work across reboots and replugs...

 

[martin8310]

The

/dev/serial/by-id

solution is the cleanest I think. Can anyone tell me how to configure it properly?

 

[martin-g-it]

1. run

ls -l /dev/serial/by-id

on the Proxmox host

Output will be something like:

root@pve101:~# ls -l /dev/serial/by-id
total 0
lrwxrwxrwx 1 root root 13 Sep  9 10:54 usb-1a86_USB_Serial-if00-port0 -> ../../ttyUSB0
lrwxrwxrwx 1 root root 13 Sep 22 18:46 usb-FTDI_FT230X_Basic_UART_D307ORET-if00-port0 -> ../../ttyUSB1

2. Go via the PVE manager to your LXC setup, choose Resources > Add > Device Passthrough
3. Enter the Device Path like

/dev/serial/by-id/<device id>

In my example /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0 for the first device, /dev/serial/by-id/usb-FTDI_FT230X_Basic_UART_D307ORET-if00-port0 for the second one

 

[martin8310]

1. run

ls -l /dev/serial/by-id

on the Proxmox host

Output will be something like:

root@pve101:~# ls -l /dev/serial/by-id
total 0
lrwxrwxrwx 1 root root 13 Sep  9 10:54 usb-1a86_USB_Serial-if00-port0 -> ../../ttyUSB0
lrwxrwxrwx 1 root root 13 Sep 22 18:46 usb-FTDI_FT230X_Basic_UART_D307ORET-if00-port0 -> ../../ttyUSB1

2. Go via the PVE manager to your LXC setup, choose Resources > Add > Device Passthrough
3. Enter the Device Path like

/dev/serial/by-id/<device id>

In my example /dev/serial/by-id/usb-1a86_USB_Serial-if00-port0 for the first device, /dev/serial/by-id/usb-FTDI_FT230X_Basic_UART_D307ORET-if00-port0 for the second one

That's how I do it at the moment, but that's not good because as soon as the device is disconnected, the CT no longer starts ;-(

 

[martin-g-it]

Hmm, didn’t face that issue.. but why disconnect the device?

 

[martin8310]

Hmm, didn’t face that issue.. but why disconnect the device?

because you unplug USB devices from time to time.