learning docker steps(10) ----在容器当中访问主机设备文件

从docker 1.2开始，我们可以在容器内部访问主机设备通过 –device命 令选项， 在早期的版本当中可以通过-v选项实现。

首先来了解一下—device的使用方法：

    --device=<Host Device>:<Container Device Mapping>:<Permissions>

如下的样例是映射usb串口进容器当中

1）  插入usb转串口设备至ubuntu当中，通过内核信息可知其枚举成/dev/ttyUSB0.

2）   

[240164.248698] usb 1-2: new full-speed USB device number 13 using xhci_hcd

[240164.523420] usb 1-2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.63

[240164.523422] usb 1-2: New USB device strings: Mfr=0, Product=2, SerialNumber=0

[240164.523423] usb 1-2: Product: USB2.0-Serial

[240165.490983] usbcore: registered new interface driver usbserial_generic

[240165.491536] usbserial: USB Serial support registered for generic

[240165.518230] usbcore: registered new interface driver ch341

[240165.518275] usbserial: USB Serial support registered for ch341-uart

[240165.518330] ch341 1-2:1.0: ch341-uart converter detected

[240165.519882] usb 1-2: ch341-uart converter now attached to ttyUSB0

2) 使用device命令选项将其映射至ubuntu容器当中：

# docker run -ti --device=/dev/ttyUSB0:/dev/ttyUSB0 ubuntu bash

3) 在容器当中查看映射之后的设备文件：

root@1faf0ed6945d:/# ls /dev/ -al

total 4

drwxr-xr-x 5 root root       380 Mar 20 05:16 .

drwxr-xr-x 1 root root      4096 Mar 20 05:16 ..

crw--w---- 1 root tty     136, 0 Mar 20 05:16 console

lrwxrwxrwx 1 root root        11 Mar 20 05:16 core -> /proc/kcore

lrwxrwxrwx 1 root root        13 Mar 20 05:16 fd -> /proc/self/fd

crw-rw-rw- 1 root root      1, 7 Mar 20 05:16 full

drwxrwxrwt 2 root root        40 Mar 20 05:16 mqueue

crw-rw-rw- 1 root root      1, 3 Mar 20 05:16 null

lrwxrwxrwx 1 root root         8 Mar 20 05:16 ptmx -> pts/ptmx

drwxr-xr-x 2 root root         0 Mar 20 05:16 pts

crw-rw-rw- 1 root root      1, 8 Mar 20 05:16 random

drwxrwxrwt 2 root root        40 Mar 20 05:16 shm

lrwxrwxrwx 1 root root        15 Mar 20 05:16 stderr -> /proc/self/fd/2

lrwxrwxrwx 1 root root        15 Mar 20 05:16 stdin -> /proc/self/fd/0

lrwxrwxrwx 1 root root        15 Mar 20 05:16 stdout -> /proc/self/fd/1

crw-rw-rw- 1 root root      5, 0 Mar 20 05:16 tty

crw-rw---- 1 root dialout 188, 0 Mar 20 05:16 ttyUSB0

crw-rw-rw- 1 root root      1, 9 Mar 20 05:16 urandom

crw-rw-rw- 1 root root      1, 5 Mar 20 05:16 zero

root@1faf0ed6945d:/# ls  -al /dev/ttyUSB0

crw-rw---- 1 root dialout 188, 0 Mar 20 05:16 /dev/ttyUSB0

root@1faf0ed6945d:/#