I'm attempting to use a loop device inside a container, to mount some image file:
> sudo losetup /dev/loop0 test.img
losetup: /dev/loop0: failed to set up loop device: No such file or directory
/dev/loop0 indeed doesn't exist, and
> sudo mknod /dev/loop0 b 7 0
mknod: ‘/dev/loop0’: Operation not permitted
How can I make this work? Does the container need some cgroup permission that it might not have?