CentOS - Dec 2015 - wifi on servers and fedora [was Re: 7.2 kernel panic on boot]

You think this is irritating, what about when you're trying to replicate the
network configuration to failover hardware...  There is a way around this, I
haven't tried it on CentOS but on Ubuntu there are kernel command line
parameters:

net.ifnames=1
biosdevname=0

which will override this behavior. Again, on Ubuntu these are added in
/etc/default/grub as parameters to GRUB_CMDLINE_LINUX_DEFAULT.  Finally,
there's /udev/rules.d/70-persistent-net.rules which allows you to associate
a MAC address with an eth? label.  However, without the command line parameters
it is ignored (contrary to other statements on the web ).  Given this is CentOS
you mileage will almost certainly vary but hopefully this gives you enough to go
on to get to the final solution.  There is a freedesktop.org web page about why
they did this - it has to do with mobile devices and plug-and-play networking. 
Take that page's statement about setting net.ifnames=0 cautiously, I found
it was the exact opposite.  biosdevname is a program written by someone at Dell
which is supposed to report on hardware configurations and make some sense out
of the cesspool.  It appears the source of the whole thing is hardware vendors
doing whatever they want and in some cases not playing by the rules.

----- Original Message -----
From: "John R Pierce" <pierce at hogranch.com>
To: centos at centos.org
Sent: Thursday, December 10, 2015 4:33:24 PM
Subject: Re: [CentOS] wifi on servers and fedora [was Re: 7.2 kernel panic on
boot]

On 12/10/2015 1:56 PM, m.roth at 5-cent.us wrote:
> As a lesser example, I just*adore*  the new ethernet names - NOT. Breaks
> scripts, makes it all more difficult, not to mention*so*  much easier to
> guess, when you've debugging a box and your organization has hardware
from
> many OEMs. What was wrong with eth0, or even em1?
when you have multiple adapters, perhaps different types (maybe 2 10gigE 
and 2 1gigE?) which one is eth0 supposed to be?   BSD has always used 
driver type in the network device names, and having dealt with device 
confusions before, I understand why.



-- 
john r pierce, recycling bits in santa cruz

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On 12/10/2015 3:05 PM, Leroy Tennison wrote:
> You think this is irritating, what about when you're trying to
replicate the network configuration to failover hardware...
IMHO, active/standby failover hardware should have exact identical 
configurations down to firmware revisions, so I'm not sure what the 
issue is.


-- 
john r pierce, recycling bits in santa cruz

On Dec 10, 2015, at 6:05 PM, Leroy Tennison <leroy at datavoiceint.com>
wrote:
> There is a freedesktop.org web page about why they did this - it has to do
with mobile devices and plug-and-play networking.  Take that page's
statement about setting net.ifnames=0 cautiously, I found it was the exact
opposite.
To be honest, I found that this change better suited servers, which often have
multiple interfaces on multiple vendor?s cards, rather than mobile devices,
which tend to only have one ethernet device, if any.  Being able to predictably
define which interface would be named is much more important when you?ve got 4
network interfaces, rather than hoping that eth0 is the one you booted from.



--
Jonathan Billings <billings at negate.org>

Unfortunately, hardware isn't always purchased at the same time and, even if
it is, how do you know that the vendor didn't make some
"transparent" change in production that isn't noticeable until you
get into the details.  Vendors ***shouldn't*** do that but then there's
reality.

----- Original Message -----
From: "John R Pierce" <pierce at hogranch.com>
To: centos at centos.org
Sent: Thursday, December 10, 2015 5:10:23 PM
Subject: Re: [CentOS] wifi on servers and fedora [was Re: 7.2 kernel panic on
boot]

On 12/10/2015 3:05 PM, Leroy Tennison wrote:
> You think this is irritating, what about when you're trying to
replicate the network configuration to failover hardware...
IMHO, active/standby failover hardware should have exact identical 
configurations down to firmware revisions, so I'm not sure what the 
issue is.


-- 
john r pierce, recycling bits in santa cruz

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The device I encountered it on had 10 NICS, at installation 6 of them got the
new naming convention and four of them got the eth convention.  I guess my
question is "what's wrong with using the MAC address?"  Yes, I
know some things don't have MAC addresses, let the exceptional situation be
the exception.

----- Original Message -----
From: "Jonathan Billings" <billings at negate.org>
To: "CentOS mailing list" <centos at centos.org>
Sent: Thursday, December 10, 2015 5:15:09 PM
Subject: Re: [CentOS] wifi on servers and fedora [was Re: 7.2 kernel panic	on
boot]

On Dec 10, 2015, at 6:05 PM, Leroy Tennison <leroy at datavoiceint.com>
wrote:
> There is a freedesktop.org web page about why they did this - it has to do
with mobile devices and plug-and-play networking.  Take that page's
statement about setting net.ifnames=0 cautiously, I found it was the exact
opposite.
To be honest, I found that this change better suited servers, which often have
multiple interfaces on multiple vendor?s cards, rather than mobile devices,
which tend to only have one ethernet device, if any.  Being able to predictably
define which interface would be named is much more important when you?ve got 4
network interfaces, rather than hoping that eth0 is the one you booted from.



--
Jonathan Billings <billings at negate.org>


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