Devnodes

Exporting devices through devnodes

You can export devices from the Hardware Node (HN) to the container (CT) by using the devnodes flag, here for example for a serial port adaptor (/dev/ttyUSB0):

$ vzctl set 1024 --devnodes ttyUSB0:rw --save

# vzctl enter 1024
entered into CT 1024
root@1024 / [1]# screen /dev/ttyUSB0 57600 8N1
[detached from 17017.pts-0.1024]
root@1024 / [2]# ls -al /dev/ttyUSB0 
crw-r----- 1 root root 188, 0 Apr 17 15:36 /dev/ttyUSB0

If you remove suddenly the device, vzctl will complain and continue:

# vzctl enter 1024
Incorrect device name /dev/ttyUSB0: No such file or directory
Invalid value for DEVNODES=ttyUSB0:rw, skipped
entered into CT 1024
root@1024 / [1]# 

Inside the container, you can set a different owner than root, thereby regulating internal access privileges possibly differently from the host system.

List of successfull exported devices

• /dev/ttyUSB0
• /dev/i2c-* (tested through i2c-parport)
• /dev/net/tun