Using biosdevname by default?

[Colin Watson]

On Mon, Feb 06, 2012 at 09:44:51AM -0600, Robbie Williamson wrote:
> Am I wrong, or did Dell request that we enable this feature by default
> for Dell Poweredge servers *only*, by detecting at boot...and that
> they had done something similar with Fedora?

I thought I covered that in my original mail:

  "Firstly, I think it is in general unwise to make this kind of change
  for a single class of machine, at least for Ubuntu itself as opposed
  to vendor-specific builds.  The effect of doing that is to divide our
  testing efforts, so that tests of relevant functionality on one class
  of machine can no longer be presumed to be valid for others.  This
  usually ends up being to the detriment of everyone: Dell servers would
  no longer be able to take advantage of the testing we do on other
  classes of system."

Now, I can see that to some extent this is the server team's problem
rather than mine, so if you're saying that the server team is willing to
take this on and fix the associated foundational issues that our
networking expert has said it's likely to trigger, then I guess that's
fine.  I just find it a slightly disturbing precedent, and it would be
very easy to end up with a distribution whose behaviour was in practice
fragmented across systems.

Furthermore, it may be that Dell requested that Fedora enable this only
for PowerEdge servers, but that's not what they appear to have actually
implemented.
http://fedoraproject.org/wiki/Features/ConsistentNetworkDeviceNaming
(owned by a Dell engineer) says:

  "This feature affects all physical systems that expose network port
  naming information in SMBIOS 2.6 or later (specifically field types 9
  and 41).  Dell PowerEdge 10G and newer servers (PowerEdge 1950 III
  family, PowerEdge R710 family, and newer), and HP ProLiant G6 servers
  and newer are known to expose this information, as do some newer
  desktop models.  Furthermore, most older systems expose some
  information in the PCI IRQ Routing Table, which will be consulted if
  information is not provided by SMBIOS."

So, without being yet decided about biosdevname by default, I'm
wholeheartedly in agreement with Fedora that it should be all or nothing
if we don't want to risk lowering the quality of Ubuntu just on
PowerEdge servers, which I'm sure isn't the goal.

> If we can contain this change to only affecting Dell servers, then any
> issues it creates would also only affect Dell servers...and I'd think
> Dell would have a self-interest in helping us resolve those asap.

On the other hand, the people who will end up being responsible for
fixing the bugs may not have desperately convenient access to Dell
servers.  By making this behaviour system-specific, we make it harder
for our own developers to track down obscure corner cases.

Personally, my preferred approach would be something like this:

 1) Come up with a QA plan for 12.04 involving installing a cohort of
    test systems with biosdevname=1 and tracking down the associated
    problems.  That would permit Dell and others to use this in
    deployments, without risking the quality of the golden 12.04 images.
    (The above Fedora specification should help, since it links to a
    number of application-specific bug reports.)

 2) At UDS, consider defaulting to biosdevname=1 for 12.10.  Presumably
    by that point we would have reasonably substantial experience with
    it as a result of 1).

Cheers,

-- 
Colin Watson                                       [cjwatson at ubuntu.com]