device_type not respected

[Dennis Kliban]

When launching an instance with block_device_mapping_v2, if source_type="image", destination_type="volume" and device_type="cdrom", the block device is attached as "disk" running on "ide" bus. Expected to be "cdrom" on "ide" bus.

example with python-novaclient: https://dpaste.de/uojBC/
libvirt.xml generated from above command: https://dpaste.de/bSw71/

[Dennis Kliban (dkliban)]

New patch produces some unexpected behavior. The 'cdrom' is now designated properly, however an extra volume of type 'file' is also created. Here are a couple of examples.

python code: https://dpaste.de/fMN0b/
xml produced: https://dpaste.de/0B42x/

python code: https://dpaste.de/quSwQ/
xml produced: https://dpaste.de/mIiSo/

[Nikola Đipanov (ndipanov)]

Hey Dennis - thanks for the thorough reports!

The disk.local disk you see appearing is intended behaviour if you have ephemeral set to a non 0 size in your flavor that you used to start the instance with (please check that this is the case).

Also - I have no idea where the <alias/> element comes from as I don't seem to get it on my system - can you make sure your devstack is updated to the latest master, and maybe write down the version of libvirt and the system you are using to try this.

[Dennis Kliban (dkliban)]

You were correct in identifying the problem. The flavor I was using had a 20Gb ephemeral disk associated with it.

[Russell Bryant (russellb)]

Ok, so sounds like this isn't a bug, right? I'm closing this out, but feel free to reopen if I misinterpreted things here.

[Dennis Kliban (dkliban)]

The patch that fixes this bug is awaiting approval. https://review.openstack.org/#/c/46298/

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/46298
Committed: http://github.com/openstack/nova/commit/b65eecf2d8b4df9330c09dd31b818bbd5c0da3cb
Submitter: Jenkins
Branch: master

commit b65eecf2d8b4df9330c09dd31b818bbd5c0da3cb
Author: Nikola Dipanov <email address hidden>
Date: Thu Sep 12 17:19:59 2013 +0200

    Libvirt: volume driver set correct device type

    Due to a typo, libvirt volume driver was assigning the device type
    passed to the connect_volume method to the wrong attribute of the
    LibvirtConfigGuestDisk class (non existing device_type which is
    completely disregarded, instead of the expected source_device), which
    caused the rendered XML to always have the device set to 'disk'. This
    patch fixes that issue.

    Also adds the 'lun' type to the list of supported device_types since it
    is supported by libvirt but was missed in the previous refactoring.

    Tests are added to prevent future regressions.

    Closes-bug: #1223890

    Change-Id: Iee160afcc23f762a752df1ca20372944d5100291

[Dennis Kliban (dkliban)]

The patch worked when I specified "device_name": "/dev/fd0", however, I still got an exception when I didn't provide a device name.

2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/compute/manager.py", line 1005, in _build_instance
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp self._default_block_device_names(context, instance, image_meta, bdms)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/compute/manager.py", line 1353, in _default_block_device_names
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp block_device_mapping)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/compute/manager.py", line 1284, in _default_device_names_for_instance
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp *block_device_lists)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/driver.py", line 4744, in default_device_names_for_instance
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp block_device_mapping)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 425, in default_device_names
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp get_disk_info(virt_type, instance, block_device_info)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 612, in get_disk_info
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp image_meta, rescue)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 574, in get_disk_mapping
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp assigned_devices=pre_assigned_device_names)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 357, in get_info_from_bdm
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp device_name = find_disk_dev_for_disk_bus(padded_mapping, bdm_bus)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 172, in find_disk_dev_for_disk_bus
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp dev_prefix = get_dev_prefix_for_disk_bus(bus)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp File "/opt/stack/nova/nova/virt/libvirt/blockinfo.py", line 141, in get_dev_prefix_for_disk_bus
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp disk_bus)
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp NovaException: Unable to determine disk prefix for None
2013-09-26 17:43:04.018 TRACE nova.openstack.common.rpc.amqp

[Nikola Đipanov (ndipanov)]

Dennis - this seems to be the wrong bug for comment #7. I believe you wanted to comment on https://bugs.launchpad.net/nova/+bug/1229273

I'll copy the comment on there.