[systemd-devel] Finding network interface name in different distro

[Etienne Champetier]

Le mar. 18 oct. 2022 à 10:11, Greg Oliver <oliver.greg at gmail.com> a écrit :
>
> On Fri, Oct 14, 2022 at 7:42 PM Etienne Champetier <champetier.etienne at gmail.com> wrote:
>>
>> Hi All,
>>
>> When changing distro or distro major versions, network interfaces'
>> names sometimes change.
>> For example on some Dell server running CentOS 7 the interface is
>> named em1 and running Alma 8 it's eno1.
>>
>> I'm looking for a way to find the new interface name in advance
>> without booting the new OS.
>> One way I found is to unpack the initramfs, mount bind /sys, chroot,
>> and then run
>> udevadm test-builtin net_id /sys/class/net/INTF
>> Problem is that it doesn't give me right away the name according to
>> the NamePolicy in 99-default.link
>>
>> Is there a command to get the future name right away ?
>
>
> I do not like the biosdevname introduced stuff for machines with 4 or less interfaces, so another option is to disable the auto-naming:
>
> biosdevname=0 net.ifnames=0
>
> on the kernel cmdline will do it.  Also, the biosdevname package needs to be installed.  This will yield the traditional ethX, wlanX, etc interface names that are ordered by default the way they used to be.  Of course, this does not scale well when you have hotplug devices with many pci ports and ethernet cards if you ever need to replace one card.  Just my $.02

I can't change the naming, and often have additional NICs (10/25G)
My full use case is to automate the installation of 'appliances'
software based on Linux
that only have manual ISO install as deployment option.
For that I boot on a live system based on Alma 8, download the ISO,
unpack it and run their install script a bit modified.
Manual and automated install must be bit for bit identical, no changes
in the appliance allowed.
One info that I need to properly create the network config is the
future interface name.