biosdevname causes issues during diskless boot.

[tschak909]

A ticket for this is here: https://git.linuxmce.org/linuxmce/linuxmce/issues/2733

When linuxmce is installed via trusty-i386 server, biosdevname is installed, which is a set of initrd scripts that attempt to name various devices, including ethernet devices, by their relative hardware position as reported by the bios:
The facility is described here:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Networking_Guide/sec-Consistent_Network_Device_Naming_Using_biosdevname.html
In our case, any embedded (LOM) ethernet devices get called emX instead of ethX, which blows up our initrd, and causes a kernel panic shortly after IP-Config successfully completes.

What I suggest, is a two pronged approach to fixing our initrd:

(1) remove biosdevname during lmce install, with a corresponding initrd update. for the short term
(2) do more testing and auditing of biosdevname to see how consistent the naming is, and adapt our scripts accordingly, for the long term.

[phenigma]

How does this 'blow' up the init rd?  Some more details would be helpful, many scripts have already been updated.  Please provide specific instructions to recreate whatever issue you are having.  Thanks.

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[tschak909]

This is espeically relevant for installs done via Ubuntu Server (in my case trusty i386)

If you read the page I linked, it shows how the ethernet device names are changed, depending on how they are located in the box.

LOM (Lan-on-Motherboard, devices built onto the motherboard) devices get a device name like emX.
PCI devices get a device name like ethX. (other distributions actually go much further than this, and mix in manufacturer specific names a la BSD).

If you have a LOM device, like I have, on a few machines, then the ethernet device is em1 (not em0), and somewhere in the initrd, a kernel panic happens. (You see this after the IP-Config messages).

removing the biosdevname package, and rebuilding the initrd solves the problem.

-Thom

[Marie.O]

Interestingly, biosdevname seems really only be installed on the server version of Ubuntu. None of my trusty installs have it installed.

[tschak909]

Yup. That seems to line up...

-Thom

[phenigma]

biosdevname is the new norm in xenial.  It is installed not typically installed on trusty.

J.

[phenigma]

And we have never supported Ubuntu server installs. 

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[Marie.O]

Correct. But it was my understanding in the past that after the Kubuntu requirement was nullified, that it basically didn't matter what Ubuntu you installed. Good to have the information that people should use the default desktop version.

[phenigma]

It shouldn't matter what version you install if they keep them consistent, I have only ever tested with the desktop version as that is what we produce DVDs of.  That being said, this is standard behaviour in Xenial now.

J.