Booting from volume fails when the device_name is not specified

[Xavier Queralt]

With current nova in master, when booting an instance using an existing volume without specifying the device_name fails with the following traceback in nova compute:

$ nova boot --boot-volume f1f2de9c-eedf-41cf-9089-a41ec0706b3e --flavor m1.custom --key-name default server --poll

2014-03-10 05:48:27.735 DEBUG oslo.messaging._drivers.amqp [-] UNIQUE_ID is 38af8a6ad88649449919434f9facd899. from (pid=21192) _add_unique_id /opt/stack/oslo.messaging/oslo/messaging/_drivers/amqp.py:338
2014-03-10 05:48:27.750 ERROR nova.compute.manager [req-f7b15296-7be8-4cc5-9e8c-1ea3658baa7e admin admin] [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] Error: '<class 'nova.objects.block_device.BlockDeviceMapping'>' object has no attribute 'mount_device'
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] Traceback (most recent call last):
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/compute/manager.py", line 1242, in _build_instance
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] bdms)
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/compute/manager.py", line 1573, in _default_block_device_names
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] root_bdm)
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/compute/manager.py", line 1530, in _default_root_device_name
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] root_bdm)
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 5084, in default_root_device_name
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] cdrom_bus)
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 422, in get_root_info
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] if not get_device_name(root_bdm) and root_device_name:
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 392, in get_device_name
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] return bdm.get('device_name') or bdm.get('mount_device')
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/objects/base.py", line 411, in get
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] self.__class__, key))
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] AttributeError: '<class 'nova.objects.block_device.BlockDeviceMapping'>' object has no attribute 'mount_device'
2014-03-10 05:48:27.750 TRACE nova.compute.manager [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660]
2014-03-10 05:48:27.753 DEBUG nova.compute.utils [req-f7b15296-7be8-4cc5-9e8c-1ea3658baa7e admin admin] [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] Build of instance 7ce5a209-49a3-417b-aa0d-0ccf066dc660 was re-scheduled: '<class 'nova.objects.block_device.BlockDeviceMapping'>' object has no attribute 'mount_device' from (pid=21192) notify_about_instance_usage /opt/stack/nova/nova/compute/utils.py:334
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] Traceback (most recent call last):
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/compute/manager.py", line 1134, in _run_instance
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] instance, image_meta, legacy_bdm_in_spec)
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] File "/opt/stack/nova/nova/compute/manager.py", line 1293, in _build_instance
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] reason=unicode(exc_info[1]))
2014-03-10 05:48:27.753 TRACE nova.compute.utils [instance: 7ce5a209-49a3-417b-aa0d-0ccf066dc660] RescheduledException: Build of instance 7ce5a209-49a3-417b-aa0d-0ccf066dc660 was re-scheduled: '<class 'nova.objects.block_device.BlockDeviceMapping'>' object has no attribute 'mount_device'
2014-03-10 05:48:27.753 TRACE nova.compute.

[Nikola Đipanov (ndipanov)]

Posted a fix here - https://review.openstack.org/#/c/79319/1

Not sure why LP didn't pick it up.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/79319
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=181bcf77c429ecdde1f28b1884f0aa9144eb0851
Submitter: Jenkins
Branch: master

commit 181bcf77c429ecdde1f28b1884f0aa9144eb0851
Author: Nikola Dipanov <email address hidden>
Date: Mon Mar 10 13:56:54 2014 +0100

    libvirt: fix blockinfo get_device_name helper

    Currently all the methods in libvirt's blockinfo module will either
    be called with block device objects (when attempting to default device
    names) or with a DriverBlockDevice subclass (all other operations in
    the virt driver that expect such format to be passed).

    This patch updates the get_device_name method to honor the above
    situation introduced by I055651b5fd415092787d9487a69467a9bbcf073e.

    Closes-bug: #1290302
    Change-Id: I7099ea4502da2108c4bcba530a8ace173d2dafc9