sys-fs/udev now has reached a milestone revision number 200. When I read the news item “2013-03-29 Upgrading udev to version >=200,” I thought the Predictable Network Interface Names had arrived much faster than I expected. I had mentally prepared for this day to come since the update of udev-197.

The emerge message told me:


* Messages for package sys-fs/udev-200:

* Removing unmodified file /etc/udev/rules.d/80-net-name-slot.rules from old udev installation to enable
* the new predictable network interface naming.
*
* The new predictable network interface names are used by default, see:
* http://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames
*
* Example command to get the information for the new interface name before booting
* (replace <ifname> with, for example, eth0):
* # udevadm test-builtin net_id /sys/class/net/<ifname> 2> /dev/null
*
* You can use kernel command net.ifnames= to control this feature.
*
* You need to restart udev as soon as possible to make the upgrade go
* into effect.
* The method you use to do this depends on your init system.
*
* For more information on udev on Gentoo, writing udev rules, and
*          fixing known issues visit:
*          http://www.gentoo.org/doc/en/udev-guide.xml

It seemed to telling me it’s coming:

Removing unmodified file /etc/udev/rules.d/80-net-name-slot.rules from old udev installation to enable the new predictable network interface naming.

But after I rebooted, eth0 is still here. However, my wlan0 had been renamed to wlp11s0:


Apr  1 08:00:39 dfed systemd-udevd[733]: renamed network interface wlan0 to wlp11s0

I haven’t brought up my wireless device, but I can see that name in /sys/class/net. So, the wired one isn’t renamed, but the wireless interface is.

I still don’t know why I still have the old names for the wired interface. I don’t have any rules, the /etc/udev/rules.d is empty, and even the news item read like saying the same thing:

  1. predictable network interface names:

If /etc/udev/rules.d/80-net-name-slot.rules is an empty file or a symlink to /dev/null, the new names will be disabled and the kernel will do all the interface naming, and the resulting names may vary by kernel configuration, hardware configuration and kernel version.

Although, I don’t quite sure what it means, whether the new names would take place or not, the words read somewhat conflicting. Either, I was ready. Well, but it just doesn’t come. LOL.

Anyway, the news item also states something makes a lot of sense:

The feature can also be completely disabled using net.ifnames=0 on the kernel command line.

If you only have one interface card, you don’t necessarily have much use for this feature as the name almost always stays at eth0, you can easily disable it using forementioned methods.

If you read the reason why Predictable Network Interface Names is created, then you know there is actually no reason for people who have only one wired interface and/or one wireless interface to have this feature enabled.

I would use net.ifnames=0 when one day the predictable names has become default for me if that day would actually come. However, that would require editing boot menu, so I simply did:


touch /etc/udev/rules.d/80-net-name-slot.rules

To create the file with no content, I restarted udev and it didn’t say anything about rename of wlan0.

So, after all my mental preparation for the big number 200 was just a big waste! I still didn’t need to do anything. Nothing is actually broken (if don’t count wlan0), still bootable, everything is still the same as before.