[lxc-users] Question on using /dev/uio0 inside containers

[Anjali Kulkarni]

Thanks Stephane for your response!
Just to be clear, if I use option 3, I use the host's device info, that is
the device has foll. Major/minor nos 249, 0 as obtained below on host:

ls -l /dev/uio0
crw------- 1 root root 249, 0 Jul  6 13:59 /dev/uio0


Hence, I add an entry in my config file like:

lxc.cgroup.devices.allow = c 249:0 rwm

And as you suggested:

lxc.mount.entry = /dev/uio0 dev/uio0 none bind,create=file

?
Anjali

On 7/7/14 8:22 AM, "Stéphane Graber" <stgraber at ubuntu.com> wrote:

>On Mon, Jul 07, 2014 at 02:59:44PM +0000, Anjali Kulkarni wrote:
>> Hi,
>> 
>> I am a newbie to using containers, and I am trying to run a DPDK
>>enabled app inside a system container (which I created using
>>lxc-create). While, lxc-execute works to run the dpdk app, the system
>>container does not, giving me the following error:
>> 
>> EAL: Cannot open /dev/uio0: No such file or directory
>> EAL: Error - exiting with code: 1
>> 
>> Where, one 10G ethernet device on host has been assigned to the uio_igb
>>driver on the host, and hence is visible from host:
>> root:/# ls /dev/uio0
>> /dev/uio0
>> 
>> But /dev/uio0 is not visible in the container.
>> 
>> I was reading about autodev and how using autodev hook you can do an
>>mknod to create the devs, but I am not sure what is the right approach
>>here.  If I look in the dev of the rootfs of the container, I see some
>>dev are already created/shared with the host. I want to do something
>>similar for /dev/uio0. Can I just share/mount the /dev/uio0 from host
>>onto container or use autodev?
>> I just want the container to be able to use the /dev/uio0 just as if on
>>host - what's the right way to approach/make this work?
>
>There are a few ways to do what you want, in any case, make sure you
>have this node listed in your cgroup.device's configuration so once it's
>there you can actually access it.
>
>I can thnk of three ways to have it available from inside the container:
> - Just mknod it by hand and use it
> - Use the lxc-device tool to add it once the container is started
> - Add this to your container's config:
>   "lxc.mount.entry = /dev/uio0 dev/uio0 none bind,create=file"
>
>The last two options expect LXC 1.0 or higher.
>
>> 
>> Thanks
>> Anjali
>> 
>> 
>
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>
>
>-- 
>Stéphane Graber
>Ubuntu developer
>http://www.ubuntu.com