Re: [libvirt] need custom /dev entries in LXC
On Wed, May 22, 2013 at 06:22:12PM -0400, Michael R. Hines wrote:
Hi,
We run nvidia devices inside libvirt-managed LXC containers.
It used to be that simply doing:
$ echo 'c 195:* rwm' > /sys/fs/cgroup/devices/libvirt/lxc
Then, after booting the container, we would do:
$ mknod -m 666 /dev/nvidia0 c 195 0
.... would be good enough to run our CUDA applications.
But, according to:
$ cat src/lxc/lxc_container.c
The CAP_MKNOD capability is being dropped and only a specific
set of devices is being created before booting the container.
Is there any reason why this is not per-device configurable?
With recent libvirt you can pass through arbitrary block and
character devices explicitly, using the following XML:
http://libvirt.org/formatdomain.html#elementsHostDevCaps
As such there is never any need to change cgroups or use
mknod as you describe.
Daniel
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