On Thu, Oct 29, 2009 at 07:25:54AM -0700, Greg KH wrote:

On Thu, Oct 29, 2009 at 08:11:25AM -0500, Matt Domsch wrote:

quoted

Netdev team - are you in agreement that having multiple names to
address the same netdevice is a worthwhile thing to add, to allow a
variety of naming schemes to exist simultaneously?  If not, this whole
discussion will be moot, and my basic problem, that the ethX naming
convention is nondeterministic, but we need determinism, remains
unresolved.

I'm still totally confused as to why you think this.  What is wrong with
what we do today, which is name network devices in a deterministic
manner by their MAC in userspace?  That name goes into the kernel, and
everyone uses the same name and is happy.

If you don't like naming by MAC, then pick some other deterministic
naming scheme that works for your hardware and write udev rules for it.

You could easily name them in a way that could keep the lowest number
(eth0) for the lowest PCI id if you so desired and your BIOS guaranteed
it.

This way the kernel has only one name, and so does userspace, and
everyone is happy.

There are two issues, which really seem distinct to me.

Users expect eth0 to map to first-onboard-nic. That's an installer
issue (since the BIOS can already export this info) and I agree that
if we want to "fix" that, we should fix it there.

Users also want to have a name that matches the way they think of
their hardware - pci slot, bios-exposed-name, mac address,
whatever. This can be done today w/ custom udev rules, and I can
visualize an installer that would generate these rules for you:

Configure a NIC
    \-> Choose NIC by: MAC/CHASSIS-NAME/PCI-SLOT
      [ Present list of unconfigured NICs by selected property ]
      \-> What name would you like to use for this interface [eth3]?
          How do you want this configured (DHCP/STATIC/..)
          ...

That would make a lot of users much happier (myself included), but it
does restrict us into one view. At different times, admins think of
their NICs by different properties. I may want to do IP assignment by
the chassis name, but then run ethereal on a specific mac address. Or
I may want to see the routes assigned to all NICs in a given PCI
slot. Sure, I can lookup all of these properties and map them back to
an interface name by hand, but aliasing provides a nice way to
short-circuit that. And, by providing a library that translates the
aliases for us, we can help ensure that all apps that want to provide
aliasing can do so in a common way.

-- 
dann frazier