Author Topic: biosdevname causes issues during diskless boot.  (Read 938 times)

tschak909

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biosdevname causes issues during diskless boot.
« on: February 26, 2017, 01:26:30 am »
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

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Re: biosdevname causes issues during diskless boot.
« Reply #1 on: February 26, 2017, 01:36:47 am »
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

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Re: biosdevname causes issues during diskless boot.
« Reply #2 on: February 27, 2017, 12:56:30 am »
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

posde

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Re: biosdevname causes issues during diskless boot.
« Reply #3 on: February 27, 2017, 11:47:22 am »
Interestingly, biosdevname seems really only be installed on the server version of Ubuntu. None of my trusty installs have it installed.

tschak909

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Re: biosdevname causes issues during diskless boot.
« Reply #4 on: February 27, 2017, 07:23:07 pm »
Yup. That seems to line up...

-Thom

phenigma

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Re: biosdevname causes issues during diskless boot.
« Reply #5 on: March 16, 2017, 02:57:40 pm »
biosdevname is the new norm in xenial.  It is installed not typically installed on trusty.

J.
« Last Edit: March 16, 2017, 03:27:21 pm by phenigma »

phenigma

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Re: biosdevname causes issues during diskless boot.
« Reply #6 on: March 16, 2017, 09:34:14 pm »
And we have never supported Ubuntu server installs. 

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posde

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Re: biosdevname causes issues during diskless boot.
« Reply #7 on: March 16, 2017, 11:25:11 pm »
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

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Re: biosdevname causes issues during diskless boot.
« Reply #8 on: March 17, 2017, 02:22:52 pm »
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.