CentOS - Feb 2016 - NICs order

Gordon Messmer wrote:
> On 02/01/2016 07:00 AM, Leroy Tennison wrote:
>> The issue here may be systemd
> ...
>> Web documentation at freedesktop.org says net.ifnames needs to be set
to zero, I found just the opposite but if it doesn't work for you try
both before giving up.
>
> Just to clarify: net.ifnames=0 disables the systemd/udev interface
renaming feature.  biosdevname=0 disables the biosdevname interface
renaming feature, which is completely separate.  If you want the
traditional, non-deterministic Linux interface naming, you must specify
both.

You call it "deterministic". I will note that it is, in fact, straight
from Sun - 20 years ago, that was the naming on the Sparc Server that I
first picked up sysadmin work. Which was fine... FOR SUN HARDWARE. For
admins and users, it's *really* NOT a great idea, given that the system
could have a m/b from any OEM, and even trying to set up a std. kickstart
is a pain with that, much less anything more arcane. Why ethx, with the
option of adding the firmware MAC address, is such a bad idea, I have no
clue.
>
> Also, if you add rules to /etc/udev/rules.d, you should rebuild your
initrd.

?!?!?!?! THAT I had never considered, nor done, and I'm sure that in
CentOS 6, I've changed things there, and just rebooted. Oh, great, I'm
getting flashes of WinDoze.

Thanks for that info, though. I need to remember that.

      mark

Once upon a time, m.roth at 5-cent.us <m.roth at 5-cent.us>
said:
> Gordon Messmer wrote:
> > Also, if you add rules to /etc/udev/rules.d, you should rebuild your
> initrd.
> 
> ?!?!?!?! THAT I had never considered, nor done, and I'm sure that in
> CentOS 6, I've changed things there, and just rebooted.
That's only necessary for things that are initialized in the initrd.
Unless you are using network boot, the initrd won't have any of the
network initialization, so rebuilding it is not necessary for changing
network-related config (including udev rules).
-- 
Chris Adams <linux at cmadams.net>

On Mon, Feb 1, 2016 at 11:34 AM, Chris Adams <linux at cmadams.net>
wrote:
>
> That's only necessary for things that are initialized in the initrd.
> Unless you are using network boot, the initrd won't have any of the
> network initialization, so rebuilding it is not necessary for changing
> network-related config (including udev rules).

Thanks for clarification.  I'd noticed that dracut will specifically
include those files, but haven't seen docs about when or how it's
used.  Given a couple of users who said things didn't work for them, I
thought rebuilding was the safest advice.