CentOS - Feb 2020 - CentOS 7 : network interface renamed from eth0 to eth1 after reboot

Am 09.02.2020 um 16:14 schrieb Nicolas Kovacs:
> Le 09/02/2020 ? 14:10, Nicolas Kovacs a ?crit?:
>> Any suggestions ?
> 
> I forgot to add. The onboard NIC is a Broadcom card.
> 
> $ lspci | grep -i net
> 02:02.0 Ethernet controller: Realtek Semiconductor Co., Ltd. 
> RTL-8100/8101L/8139 PCI Fast Ethernet Adapter (rev 10)
> 02:09.0 Ethernet controller: Broadcom Inc. and subsidiaries BCM4401-B0 
> 100Base-TX (rev 02)
> 
> This card gets randomly renamed to either eth0 or eth1 after every reboot.
> 
> This is weird.

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/networking_guide/sec-Troubleshooting_Network_Device_Naming

Example 11.4

"Kernel always uses the ethX naming convention at boot when it 
enumerates network devices. Due to parallelization, the order of the 
kernel interface enumeration is expected to vary across reboots."

Alexander

Le 09/02/2020 ? 16:54, Alexander Dalloz a ?crit?:
> "Kernel always uses the ethX naming convention at boot when it
enumerates
> network devices. Due to parallelization, the order of the kernel interface 
> enumeration is expected to vary across reboots."
Thanks for the heads up.

I experimented quite a bit, and found some surprising behavior. So I documented 
everything in a little blog article.

   * https://www.microlinux.fr/interfaces-reseau-persistantes/

Cheers,

Niki

-- 
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On Sun, 9 Feb 2020 at 13:51, Nicolas Kovacs <info at microlinux.fr> wrote:
> Le 09/02/2020 ? 16:54, Alexander Dalloz a ?crit :
> > "Kernel always uses the ethX naming convention at boot when it
> enumerates
> > network devices. Due to parallelization, the order of the kernel
> interface
> > enumeration is expected to vary across reboots."
>
> Thanks for the heads up.
>
> I experimented quite a bit, and found some surprising behavior. So I
> documented
> everything in a little blog article.
>
>    * https://www.microlinux.fr/interfaces-reseau-persistantes/
>
> Cheers,
>
So yeah if there are certain cards, certain bios firmware, the eth? are not
guarenteed. The upstream kernel will say it is not a bug as everything is
doing what it is doing, and will point out various things where eth? is
really an internal kernel representation which is only accurate by luck.
What you are supposed to do is rename the interface (I think the docs I
found said net0 or whatever you want) and link the two via udev or similar
rules. That way the udev sets up and sees 'this pci/network is blah.. alias
it to net0 and pass that so the scripts work. Then network-scripts or
networkmanager or whatever sets up and down net0 versus a 'semi-random'
eth
interface. [For kernels beyond 4.?? and beyond I am expecting that this
will be a more stringent requirement]

-- 
Stephen J Smoogen.

There may be ways to force NIC naming, I've done so but only on Ubuntu so
you'll need to do the research if it's important to you.  Things to look
for based on my experience: 70-persistent-net.rules, net.ifnames=0,
biosdevname=0.

________________________________
From: CentOS <centos-bounces at centos.org> on behalf of Nicolas Kovacs
<info at microlinux.fr>
Sent: Sunday, February 9, 2020 12:51 PM
To: centos at centos.org <centos at centos.org>
Subject: [EXTERNAL] Re: [CentOS] CentOS 7 : network interface renamed from eth0
to eth1 after reboot

Le 09/02/2020 ? 16:54, Alexander Dalloz a ?crit :
> "Kernel always uses the ethX naming convention at boot when it
enumerates
> network devices. Due to parallelization, the order of the kernel interface
> enumeration is expected to vary across reboots."
Thanks for the heads up.

I experimented quite a bit, and found some surprising behavior. So I documented
everything in a little blog article.

   *
https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.microlinux.fr%2finterfaces-reseau-persistantes%2f&c=E,1,apWInXfONKIS7FI-2r96hzoROBMB28lpEncRGtBCvS-yWk5DU4roROpidqfC06FNDn2rlEYO-xJjHn2B0klz4_h1y7kiuBvlSjCMer8MBCuMgAcKUg,,&typo=1

Cheers,

Niki

--
Microlinux - Solutions informatiques durables
7, place de l'?glise - 30730 Montpezat
Site :
https://linkprotect.cudasvc.com/url?a=https%3a%2f%2fwww.microlinux.fr&c=E,1,egz8jO853imKX3mT5r9bs5vOCANcassZ0dea14ELcSZMwyZ5fJhfqPU6G1SltXyA8jjCrUwRU-k0Hj5oXsh2RioeNQj-7HsnfPYs1pYwHt6Vnp0cvNSVHpBAPA,,&typo=1
Mail : info at microlinux.fr
T?l. : 04 66 63 10 32
Mob. : 06 51 80 12 12
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