Fedora 15 Changes Network Device Naming Scheme

dkd903 writes "Fedora developer Matt Domsch has announced that Fedora 15 is breaking the conventional ethX naming scheme used for Ethernet devices by adopting a new scheme called Consistent Network Device Naming. The ethX naming scheme works fine as long as the system has only one Ethernet port. However if there are more than one Ethernet ports, the actual problem starts."

Comments

False

[Issarlk]

"However if there are more than one Ethernet ports, a sort of race condition develops at every system boot and the ports may get their names in an arbitrary order"

Wrong, udev handles this very fine. This is a complicated solution to a non-problem.

Re:False

[jnelson4765]

Actually, it doesn't. The interfaces can be named the same on reboot, but the initial numbering is semi-random.

The problem arises when you're trying to deploy a large number of machines, and you know which devices are where on the PCI buses (modern servers are coming with 4 Ethernet ports on the motherboard now). That way, you can assign VLANs and IPs to specific ports in a kickstart file and the installer doesn't have to play the "which interface is eth1" game. Which is not fun. We should not be relying on automagic configuration for something as basic as ethernet...

<rant>this is why I don't like the /dev/sd* interfaces in Linux - you have to dig deep into /proc to find out which port SATA and SAS devices are on</rant>

This doesn't get into crappy BIOSes that enumerate devices badly, or NICs that have a bad habit of initializing late.

Re:False

[msauve]

There are multiple issues, some of which have already been solved:

Persistency: once eth0, always eth0 - this is what most commentators here seem to think this is all about, but it's already taken care of by udev with most modern distributions.

Enumeration: Lacking previous knowledge, the order in which interfaces are enumerated. I would think this would be deterministic, but you say it's random (what is "semi-random?"). I'll take your word for it. It seems this is the problem they're trying to address. MAC addresses are indeed useless for this, in a general case, since we may be trying to enumerate ports on plug in boards (e.g. there's no guarantee the MAC in slot 1 will be lower than the MAC in slot 2).

Naming: The article says they're changing the naming. This is what makes no sense. It's not "required." ethx is just fine, as long as the names are enumerated consistently (meaning that on two "identical" boxes, the order is identical based on physical port).

Re:Article is a joke and false

[characterZer0]

With the existing system, if you wipe the disk and reinstall, will the interface names always be the same? It sounds like that is what they are trying to ensure. It could be helpful for frequently re-imaged machines and for diagnostics.