nova overwrites hw_disk_bus image property with incorrect value

[cds]

Currently using Havana

Booting from a snapshot with the image property 'hw_disk_bus' = ide boots fine initially. Shutting down/restarting the instance via the dashboard overwrites this value with 'virtio' in the libvirt.xml definition. The value in glance and nova image is correct.

 glance image-show b2e157f7-d244-4f61-afdf-d39af63f67c6
+---------------------------------------+--------------------------------------+
| Property | Value |
+---------------------------------------+--------------------------------------+
| Property 'base_image_ref' | e8ce2f05-f399-4e8f-aa98-c38a8b9d9fbb |
| Property 'hw_disk_bus' | ide |
| Property 'image_location' | snapshot |
| Property 'image_state' | available |
| Property 'image_type' | snapshot |
| Property 'instance_type_ephemeral_gb' | 0 |
| Property 'instance_type_flavorid' | 550ac351-fa21-4315-8309-bec97f00536b |
| Property 'instance_type_id' | 24 |
| Property 'instance_type_memory_mb' | 4096 |
| Property 'instance_type_name' | windows7 |
| Property 'instance_type_root_gb' | 35 |
| Property 'instance_type_rxtx_factor' | 1 |
| Property 'instance_type_swap' | 2000 |
| Property 'instance_type_vcpus' | 2 |
| Property 'instance_uuid' | b34995bc-50f6-4a9f-bc54-f8b62f0b69eb |
| Property 'os_type' | None |
| Property 'owner_id' | 473a5f18d57a4746abfb3d6ed33cea45 |
| Property 'user_id' | 40caf1d1cb994fbfb8c905e68d07b283 |
| checksum | fdad2f12773319dfa8a71dac3cdd4e5a |
| container_format | bare |
| created_at | 2014-04-29T17:29:57 |
| deleted | False |
| disk_format | qcow2 |
| id | b2e157f7-d244-4f61-afdf-d39af63f67c6 |
| is_public | True |
| min_disk | 35 |
| min_ram | 2048 |
| name | pre-migration |
| protected | False |
| size | 12756713472 |
| status | active |
| updated_at | 2014-05-12T14:27:25 |
+---------------------------------------+--------------------------------------+

nova image-show b2e157f7-d244-4f61-afdf-d39af63f67c6
+-------------------------------------+--------------------------------------+
| Property | Value |
+-------------------------------------+--------------------------------------+
| metadata owner_id | 473a5f18d57a4746abfb3d6ed33cea45 |
| minDisk | 35 |
| metadata instance_type_name | windows7 |
| metadata instance_type_swap | 2000 |
| metadata instance_type_memory_mb | 4096 |
| id | b2e157f7-d244-4f61-afdf-d39af63f67c6 |
| metadata instance_type_rxtx_factor | 1 |
| metadata os_type | None |
| metadata image_state | available |
| metadata image_location | snapshot |
| minRam | 2048 |
| status | ACTIVE |
| updated | 2014-05-12T14:27:25Z |
| metadata instance_type_id | 24 |
| metadata instance_type_vcpus | 2 |
| metadata base_image_ref | e8ce2f05-f399-4e8f-aa98-c38a8b9d9fbb |
| progress | 100 |
| metadata instance_type_flavorid | 550ac351-fa21-4315-8309-bec97f00536b |
| OS-EXT-IMG-SIZE:size | 12756713472 |
| metadata image_type | snapshot |
| metadata user_id | 40caf1d1cb994fbfb8c905e68d07b283 |
| name | pre-migration |
| created | 2014-04-29T17:29:57Z |
| metadata instance_uuid | b34995bc-50f6-4a9f-bc54-f8b62f0b69eb |
| server | b34995bc-50f6-4a9f-bc54-f8b62f0b69eb |
| metadata instance_type_root_gb | 35 |
| metadata hw_disk_bus | ide |
| metadata instance_type_ephemeral_gb | 0 |
+-------------------------------------+--------------------------------------+

The libvirt.xml of the instance
   <disk type="file" device="disk">
      <driver name="qemu" type="qcow2" cache="none"/>
      <source file="/var/lib/nova/instances/9aeb0a88-513f-4334-bb89-774e8c1d9dbf/disk"/>
      <target bus="virtio" dev="vda"/>
    </disk>
    <disk type="file" device="disk">
      <driver name="qemu" type="qcow2" cache="none"/>
      <source file="/var/lib/nova/instances/9aeb0a88-513f-4334-bb89-774e8c1d9dbf/disk.swap"/>
      <target bus="virtio" dev="vdb"/>
    </disk>

[cds (craigshannonx)]

Workaround is to snapshot the image which was shutdown and redeploy it.

[Nikola Đipanov (ndipanov)]

Yes - it seems that we need to pass in the image_meta to power_on driver method. I'm looking if we can do it without a roundtrip to glance.

We really should make libvirt.blockinf.get_disk_info (the method that exctracts these kind of things from the image metadata) always require the data to be passed and not make it optional.

[Nikola Đipanov (ndipanov)]

Ah so looks like this is actually fixed in icehouse - we just need to backport it to Havana. See https://bugs.launchpad.net/nova/+bug/1255449 and the related fix.

Let me close this is a dublicate of that - and I will propose a backport for havana stable there.