#4491 Switch Ubuntu /dev to devtmpfs

[Matt Ezell]

I installed Mellanox OFED into a diskless node, but it never created the /dev/infiniband devices.

Historically, udev was responsible for creating devices in /dev. Since Linux kernel 2.6.32 the /dev file system should be of type devtmpfs. Newer udevs (like the one that ships with Ubuntu 14.10) won't make device nodes anymore.

If you modify genimage to mount /dev as devtmpfs instead of tmpfs, things work as expected. Additionally, you can get rid of many of the mknod lines, since the kernel will make them for you.

[Matt Ezell]

See attached patch

[Anonymous]

Er Tao - Could you take a look at this bug, or reassign if you are not the correct person? Thanks!

[zhao er tao]

You are right that devtmpfs can automatically create dev node that kernel need.
I Checked in the code with hash num 7722f97afa0d27379a504435f5d87b6940b88a32 for
master and 1ab5442ac7451f14e042cb813e5499a760fcd262 for 2.9.