"nova show" does not return block device mapping

[Tyler North]

Using nova/stable/icehouse

A "nova show instance_id" command as well as "nova.servers.get(instance_id)" with the Python API does not show the block device mapping information for the instance.

This would be useful for boot from volume instances to check attributes such as "delete_on_termination", or see which volume attached to an instance is its root volume.

[Tyler North (ty-north)]

Some command outputs to show what I mean

(openstack)~>nova show be560c45-1816-4a5f-8b98-7d96f7d40dbc
+--------------------------------------+----------------------------------------------------------+
| Property | Value |
+--------------------------------------+----------------------------------------------------------+
| OS-DCF:diskConfig | MANUAL |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-STS:power_state | 1 |
| OS-EXT-STS:task_state | - |
| OS-EXT-STS:vm_state | active |
| OS-SRV-USG:launched_at | 2015-06-30T19:37:39.000000 |
| OS-SRV-USG:terminated_at | - |
| accessIPv4 | |
| accessIPv6 | |
| config_drive | |
| created | 2015-06-30T19:37:25Z |
| flavor | m1.small (2) |
| hostId | 6619a30568af2c081d4ec495bf1f17c955f6b243ba37861874a0fb51 |
| id | be560c45-1816-4a5f-8b98-7d96f7d40dbc |
| image | Ubuntu 14.04 (839dfad2-2e9b-44e9-a127-f9ba3a8cca20) |
| key_name | Tyler |
| metadata | {} |
| name | test-vm |
| os-extended-volumes:volumes_attached | [{"id": "60dbeea2-60b3-46a5-9e92-023dd38868b4"}] |
| private network | 10.44.3.6 |
| progress | 0 |
| security_groups | ssh |
| status | ACTIVE |
| tenant_id | f39d41a7b9ef489491a57ef9b25fc4ed |
| updated | 2015-06-30T19:37:39Z |
| user_id | b4793cfa795c47c3a4c9ac10b01a2d17 |
+--------------------------------------+----------------------------------------------------------+

(openstack)~>cinder list | grep be560c45-1816-4a5f-8b98-7d96f7d40dbc
| 60dbeea2-60b3-46a5-9e92-02...

[jichenjc (jichenjc)]

sorry, but is this you are looking for?
 os-extended-volumes:volumes_attached | [{"id": "60dbeea2-60b3-46a5-9e92-023dd38868b4"}] |

[Tyler North (ty-north)]

No not really, I know I can get that information from Cinder as well, but it would be good to expose the entire block device mapping in nova so I can see:
- what device its currently attached as (/dev/vda or vdb or whatever)
- whether or not deletion_on_terminate was set

[melanie witt (melwitt)]

It looks like the "delete_on_termination" field was added to the response in API microversion 2.3 [1] along with the "root_device_name" field. Are those the fields you're interested in, or are there others?

[1] https://review.openstack.org/#/c/155853/

[Markus Zoeller (markus_z) (mzoeller)]

It looks like the Nova API provides the requested fields. So I remove
it from the list of affected projects. I also remove the "api" tag.
This is now a python-novaclient only bug report. To be specific, it is
a RFE which are usually done via blueprints [1][2] and not via bug reports.

References:
[1] https://blueprints.launchpad.net/nova/
[2] https://wiki.openstack.org/wiki/Blueprints