[CentOS] CentOS 6 : Network Interface Naming

Fri Nov 15 19:33:28 UTC 2013
Scott Robbins <scottro at nyc.rr.com>

On Fri, Nov 15, 2013 at 01:50:18PM -0500, SilverTip257 wrote:
> Hello All,
> I have one CentOS 6 KVM virtualization server that I built around a year
> ago (best I can tell it was in October 2012) at which time I would have
> been installing 6.3 [0].  That particular install used the Consistent
> Network Device Naming [1] conventions (PCIe NICs are p1p1, p1p2).

This regression is a combo RedHat/Dell idea, IIRC.  That may be why it's
that way on a Dell machine.  On Fedora, which usually shows what new
regressions will be in RH, it's gotten harder to fix with each iteration. 

To make it worse, at least on Fedora (and again, many of their ideas,
whether good or bad for servers, get into RedHat) has apparently now been
intertwined with systemd.  At first, one simply had to remove the
biosdevnames rpm to fix it.  Now, one has to do that, and also add, (in
Fedora, with grub2) net.ifnames=0 to the kernel line.  (Note that this was
for Fedora 19, not sure if they at least removed biosdevnames in F20).

To make it even more of a mess, (again, this is judging from Fedora, which
is good to keep on hand to see what new decisions good and bad will be made
by RH), I think biosdevnames gave it one name and then the whole systemd
thing gave it another.  So, it would boot up as say p12p but in
/etc/sysconfig/network-scripts it would show up as ifcfg-p1p2p or something
like that. (I'm making these names up, but that was the general idea.)

Some people consider it a good thing, especially when moving drives between
machines, but aside from it being something new, which isn't necessarily
improved, it breaks various working scripts.  

Like you, I consider it a regression, but of course, that's only my
opinion, and many experienced folks disagree, thinking it's a good
thing--although I'm sure that even they would agree that they better figure
out if biosdevname or something else will be handling it so that it is at
least consistent.

Actually, I think (but am not sure, that in VMs, even Fedora will use the
eth0, eth1 system rather than the new naming scheme.  Not just KVM, but
also VirtualBox, VMware, and so on--that has been my experience with CentOS
VMs at least. 

Scott Robbins
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