Cannot launch whole disk image with xen+libvirt

[Alvaro Lopez]

Hi.

I am unable to launch an instance with a whole-disk image (that is, a file containing a full disk with partitions).

The generated XML file for libvirt contains the following:

      <os>
        <type>xen</type>
        <root>/dev/xvda</root>
        <boot dev="hd"/>
      </os>

So when the machine starts it fails since the above is passed as a cmdline "root=/dev/xvda" being passed to the kernel that pygrub is launching, resulting in the following error during boot:

    mount: mounting /dev/xvda on /root failed: Invalid argument
    mount: mounting /dev on /root/dev failed: No such file or directory
    mount: mounting /sys on /root/sys failed: No such file or directory
    mount: mounting /proc on /root/proc failed: No such file or directory
    Target filesystem doesn't have requested /sbin/init.
    No init found. Try passing init= bootarg.

Removing that line from the libivrt XML solves this issue.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/58999

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/58999
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=5453732235d0d1a7bee0c2347b3cf8bb38a1d38f
Submitter: Jenkins
Branch: master

commit 5453732235d0d1a7bee0c2347b3cf8bb38a1d38f
Author: Alvaro Lopez Garcia <email address hidden>
Date: Thu Nov 28 09:56:41 2013 +0100

    Do not set root device for libvirt+Xen

    Currently we are setting the root device for Xen when using libvirt.
    When a user is booting an image that contains a full partitioned disk it
    fails, since the root device will be passed as "root=/dev/whatever" as
    the cmdline to the booting kernel.

    Closes-Bug: 1253626
    Change-Id: Ia5e3ee8891759c68ee51b219d1a7f80d0afbeffc