[Openstack] Ubuntu run instance error + xen

Scott Moser smoser at ubuntu.com
Thu Aug 25 20:29:39 UTC 2011


On Thu, 18 Aug 2011, Joshua Harlow wrote:

> Hi all,
>
> On xen + openstack diaboli-3 when running an instance with the generic ubuntu UEC images  from http://wiki.openstack.org/RunningNova#Registering_the_image  I am seeing the following:
>
> [    0.210681] VFS: Cannot open root device "xvda" or unknown-block(0,0)
> [    0.210691] Please append a correct "root=" boot option; here are the available partitions:
> [    0.210708] ca00            8192 sda driver: vbd
> [    0.210720] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Is there a reason you're not using pv-grub ?
The Ubuntu images that run on Amazon EC2 (xen) use pv-grub.  That allows
xen to essentially read the configuration from inside the image.   Inside
the image, it says to use a ramdisk and use LABEL=uec-images.

Without a "loader" of some sort, you're never *ever*  going to be able to
get all guest images supported with a single linux command line.


Regarding the maverick and earlier "sda" hack, that was basically forced
upon us because amazon had made the same decision you did, but chose
"root=/dev/sda1".  So, our kernel was forced to enumerate xen devices on
the sdX convention.

Scott




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