xenserver boot from iso broken

[Antony Messerli]

Created a record in Glance for an iso using this format.

glance image-create --name=name_iso --disk_format=iso --container_format=bare < name_iso.iso

When booting that image, nova-compute errors at this point after bring the iso down:

2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] Traceback (most recent call last):
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] File "/opt/rackstack/1.61/nova/lib/python2.6/site-packages/nova-2013.1-py2.6.egg/nova/virt/xenapi/vmops.py", line 477, in spawn
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] kernel_file, ramdisk_file)
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] File "/opt/rackstack/1.61/nova/lib/python2.6/site-packages/nova-2013.1-py2.6.egg/nova/virt/xenapi/vmops.py", line 193, in inner
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] rv = f(*args, **kwargs)
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] File "/opt/rackstack/1.61/nova/lib/python2.6/site-packages/nova-2013.1-py2.6.egg/nova/virt/xenapi/vmops.py", line 395, in create_vm_record_step
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] vdis, disk_image_type, kernel_file, ramdisk_file)
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] File "/opt/rackstack/1.61/nova/lib/python2.6/site-packages/nova-2013.1-py2.6.egg/nova/virt/xenapi/vmops.py", line 546, in _create_vm_record
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] vdis['root']['ref'], disk_image_type, instance['os_type'])
2013-03-13 17:23:59 18434 TRACE nova.utils [instance: 573984f7-5263-41cb-bc4e-0a54bfad01bc] KeyError: 'root'

[Chris Behrens (cbehrens)]

Try adding vm_mode=hvm to that image. The code that bombed is trying to determine pv or hvm from the 'disk'.

[Chuck Short (zulcss)]

Antony,

Did you try what Chris suggested?

chuck

[Antony Messerli (antonym)]

I did, I added vm_mode=hvm as a property and then launched a new instance and I ended up with a similar error but at a different location:

2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] Traceback (most recent call last):
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] File "/opt/rackstack/152.23/nova/lib/python2.6/site-packages/nova-2013.1.a4348.gde182d6-py2.6.egg/nova/virt/xenapi/vmops.py", line 492, in spawn
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] attach_disks_step(undo_mgr, vm_ref, vdis, disk_image_type)
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] File "/opt/rackstack/152.23/nova/lib/python2.6/site-packages/nova-2013.1.a4348.gde182d6-py2.6.egg/nova/virt/xenapi/vmops.py", line 200, in inner
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] rv = f(*args, **kwargs)
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] File "/opt/rackstack/152.23/nova/lib/python2.6/site-packages/nova-2013.1.a4348.gde182d6-py2.6.egg/nova/virt/xenapi/vmops.py", line 420, in attach_disks_step
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] injected_files)
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] File "/opt/rackstack/152.23/nova/lib/python2.6/site-packages/nova-2013.1.a4348.gde182d6-py2.6.egg/nova/virt/xenapi/vmops.py", line 587, in _attach_disks
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] cd_vdi = vdis.pop('root')
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862] KeyError: 'root'
2013-03-19 23:43:32.435 686 TRACE nova.utils [instance: 2448ef95-a2b9-4b14-82d8-380062513862]

[John Garbutt (johngarbutt)]

I would try replace vdis.pop('root') with 'iso'
(You can see ImageType in vm_utils for how this is all defined)

The next issue is vm_utils.fetch_blank_disk
It doesn't exist anymore, as far as I see.

vm_utils._generate_disk should do some of the hard work though.
just need to get root_gb from instance type I guess, for the size.

The above will not support boot from volume though.
You could check for a root, and if not pressent create a blank disk.

Maybe I will take a look at this, if I get chance...

[John Garbutt (johngarbutt)]

PS, the above issue is a bug too, Chris's suggestion is just a workaround.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/24895

[John Garbutt (johngarbutt)]

I got an ISO boot VM started, with the above hacks, but it seemed unable to boot from my CD image.

[John Garbutt (johngarbutt)]

Started some basic docs to help other create an ISO SR:
https://wiki.openstack.org/wiki/XenServer/BootFromISO

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/24895
Committed: http://github.com/openstack/nova/commit/b1445e7e84b720ac232541ef866fbe7a59faeaf8
Submitter: Jenkins
Branch: master

commit b1445e7e84b720ac232541ef866fbe7a59faeaf8
Author: John Garbutt <email address hidden>
Date: Wed Mar 20 11:56:29 2013 +0000

    xenapi: fix support for iso boot

    Fixes bug 1154731 that stated the iso support was broken.

    There were several issues around a vdis list without a 'root' disk.

    Because the ISO boot was HVM, only 0-3 devices will work, so, the
    devices used have been re-ordered to ensure ISOs can be read
    by a HVM guest without PV tools. Once PV tools are present, a
    HVM guest will be able to access an ephemeral or swap disk.

    Change-Id: I4b57f70301a4256fa975323d7964fde19e8d4508