[Bug 611144] [NEW] eucalyptus should support booting multiboot image

[Scott Moser]

Public bug reported:

Currently, for each instance launched by Eucalyptus, an admin provided kernel is booted.  Eucalyptus generates a hunk of libvirt xml like the following:
    <os>
    <type>hvm</type>
        <kernel>BASEPATH/kernel</kernel>
        <cmdline>root=/dev/sda1 console=ttyS0</cmdline>
    </os>

The result is that kvm is invoked with '-kernel <path/kernel>' and
'-append root=/dev/sda1 console=ttyS0'.

Historically, the admin provided kernel has been a linux kernel.  This
is in keeping with EC2's practice.  Recently, amazon has exposed the
ability to "boot your own kernel" by providing pv-grub as a "kernel".
The pv-grub boot loader functions very much like a normal "grub 0.97"
loader.  It reads a menu.lst from /boot/grub/menu.lst and boots kernels
from inside the guest.

The largest end user benefit of this is that now the operating system
booted can manage its own kernel.  Previously, a kernel upgrade in an
instance would result in the same kernel being used on reboot.

Eucalyptus should provide a way to load a boot loader, rather than
limiting the 'kernel' to a linux kernel.

===

The truth is, that Eucalyptus does not enforce that the kernel must be a
linux kernel.  And, a multiboot complient kernel can actually be booted
in the mechanism described above, thanks to kvm '-kernel' being a
multiboot complient boot loader.

This sounds like a perfectly simple solution: Let the admin create
multiboot compliant boot loader image (ie, grub2) that would chainload
to the grub installed in the image.

In fact, it actually *almost* works.  The problem with the simple
solution is that eucalyptus uses scsi as its root device, and seabios
has no native support for scsi (bug 611142).

Because this is *major* functionality, I'm seeking a work around to the
issue above.

--
[1] http://aws.typepad.com/aws/2010/07/use-your-own-kernel-with-amazon-ec2.html

ProblemType: Bug
DistroRelease: Ubuntu 10.10
Package: eucalyptus-nc 2.0~bzr1211-0ubuntu1
ProcVersionSignature: User Name 2.6.32-305.9-ec2 2.6.32.11+drm33.2
Uname: Linux 2.6.32-305-ec2 i686
Architecture: i386
Date: Thu Jul 29 03:15:18 2010
Ec2AMI: ami-e930db80
Ec2AMIManifest: ubuntu-images-testing-us/ubuntu-maverick-daily-i386-server-20100727.manifest.xml
Ec2AvailabilityZone: us-east-1b
Ec2InstanceType: m1.small
Ec2Kernel: aki-407d9529
Ec2Ramdisk: unavailable
ProcEnviron:
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: eucalyptus

** Affects: eucalyptus
     Importance: Undecided
         Status: New

** Affects: eucalyptus (Ubuntu)
     Importance: Undecided
     Assignee: Scott Moser (smoser)
         Status: New


** Tags: apport-bug maverick uec-images

-- 
eucalyptus should support booting multiboot image
https://bugs.launchpad.net/bugs/611144
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