Don’t trust the Tahr

Beware that since latest Ubuntu kernel upgrades (14.04.02), you may lose network rebooting your servers!

I’ve had the problem four days ago, rebooting one of my OpenNebula hosts. Still unreachable after 5 minutes, I logged in physically, to see all my “p1pX” and “p4pX” interfaces had disappeared.
Checking udev rules, there is now a file fixing interfaces mapping. On a server I have not rebooted yet, this file doesn’t exist.

The story could have ended here. But with Ubuntu, updates is a daily struggle: today, one of my ceph OSD (hosting 4 disks) spontaneously stopped working.
Meaning: the host was still there, I was able to open a shell using SSH. Checking processes, all ceph osd deamon were stopped. Starting them showed no error, while processes were still absent. Checking dmesg, I had several lines of SSL-related segfaults.
As expected, rebooting fixed everything, from ceph, to my network interfaces names.
It’s in these days I most enjoy freelancing: I can address my system and network outages in time, way before it’s too late.

While I was starting to accept Ubuntu as safe enough to run production services, renaming interfaces on a production system is unacceptable. I’m curious to know how Canonical dealt with that providing BootStack and OpenStack-based services.

Note there is still a way to prevent your interfaces from being renamed:

# ln -s /dev/null /etc/udev/rules.d/75-persistent-net-generator.rules