Problem with USB pass-thru using a symlink

S

sumnerboy

New Member
Jul 30, 2015
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Hi there,

First time poster and pretty green Proxmox user, but have been very impressed in my experiences so far.

I have managed to migrate my entire home automation server to a new box running Proxmox with debian containers. The last thing I am really struggling with is getting my two USB dongles (Z-Wave and RFXCOM) to pass-thru to my openHAB container (which accesses the dongles).

I have setup a udev rule on the host to symlink each dongle to /dev/zwave and /dev/rfxcom (which is what I had on the original Ubuntu server). This is working fine.

I then added these two devices to my container config file;

Code: 
DEVNODES="rfxcom:rw zwave:rw "

When I restart the container and enter it, I can't see either /dev/zwave or /dev/rfxcom. But I can see the actual devices from the host, i.e. /dev/ttyUSB1 and /dev/ttyUSB2.

Any ideas why these symlinks are not being persisted when I restart?

Another thing to note, if I run;

Code: 
vzctl set 104 --devnode zwave:rw --save

on the host and enter the container I can see /dev/zwave no worries - but as soon as I restart the container it is lost, and I only have the ttyUSB device available.

I have read so many threads about this and can't seem to find anything obvious which leads me to think I am doing something stupid but I have tried everything I have come across.

If anyone has any suggestions or tips I will be all ears!!

Thanks in advance,
Ben
 
Hi again,

So is this something that *just works* for others? Or am I doing something a little out of the ordinary here?

I would have thought this was a relatively common scenario. Surely if you have USB devices getting passed-thru you need to use udev rules to ensure they are available at the same mount point on both the host and your containers?

Cheers,
Ben
 
I am starting to wonder if I have failed to follow some sort of forum etiquette or guidelines? I apologise if so, I would appreciate it if someone pointed out what I have done wrong otherwise.

I also apologise for bumping this thread (twice in the last week) but I am really at a dead end currently with this problem.
 
I am using containers rather than VMs unfortunately. I managed to get it working after noticing the symlinks were being created in my container under /lib/udev/devices/<name>. They weren't being created with the correct permissions but I added a chown and chmod to my rc.local and then updated my home automation software to access the devices via the /lib/udev/devices/<name> path and things seem to be working ok so far. I can restart the container and the device is re-created, with the necessary permissions, and my software can access them ok. I have seen a few strange issues when restarting the automation software, with 'device is in use' exceptions, but I can't be sure if that is related (although I have never seen these errors when access /dev/<name> symlinks on a non-container env).

Anyway - I am happy enough that I can restart with a bit more confidence now, knowing the system will come back up again.
 
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