Describing VMs with volumes cause error 500

[Enol Fernández]

Images with attached volumes can be created and listed but when describing them an error 500 is returned to the user:

$ occi -e $OCCI_ENDPOINT --auth x509 --user-cred $X509_USER_PROXY --voms -a create -r compute -t occi.core.title="enolvm" -M $OS_TPL -M $RES_TPL -j $OCCI_ENDPOINT/occi/storage/51e347ce-9c8d-4271-8982-2d160cec1f01
http://<endpoint>/occi/compute/e7e1a4e3-4101-4fcb-acf1-dfa8df3b8148

occi -e $OCCI_ENDPOINT --auth x509 --user-cred $X509_USER_PROXY --voms -a describe -r http://<endpoint>/occi/compute/e7e1a4e3-4101-4fcb-acf1-dfa8df3b8148
F, [2017-02-10T07:12:43.412783 #6322] FATAL -- : [rOCCI-cli] An error occurred! Message: Net::HTTP::Get failed! HTTP Response status: [500] Internal Server Error : "The server has either erred or is incapable of performing the requested operation."

The VM can however be described via OpenStack native API:
$ openstack server show e7e1a4e3-4101-4fcb-acf1-dfa8df3b8148
+--------------------------------------+-------------------------------------------------------------------------------------------------------+
| Field | Value |
+--------------------------------------+-------------------------------------------------------------------------------------------------------+
| OS-DCF:diskConfig | MANUAL |
| OS-EXT-AZ:availability_zone | nova |
| OS-EXT-STS:power_state | NOSTATE |
| OS-EXT-STS:task_state | spawning |
| OS-EXT-STS:vm_state | building |
| OS-SRV-USG:launched_at | None |
| OS-SRV-USG:terminated_at | None |
| accessIPv4 | |
| accessIPv6 | |
| addresses | |
| config_drive | |
| created | 2017-02-10T07:14:02Z |
| flavor | tiny (6) |
| hostId | 738d8ae77266bbc2d8c22e514a5018047290f3f4efa4c31ace525dd3 |
| id | e7e1a4e3-4101-4fcb-acf1-dfa8df3b8148 |
| image | Image for EGI Ubuntu 14.04 [Ubuntu/14.04/VirtualBox]_EGI_fedcloud (43aa9fe8-0cde- |
| | 4a35-87b8-eda324f8f1b8) |
| key_name | None |
| name | enolvm |
| os-extended-volumes:volumes_attached | [{u'id': u'51e347ce-9c8d-4271-8982-2d160cec1f01'}] |
| progress | 0 |
| project_id | 02e47ef981904ceaa30f7c545e563a11 |
| properties | |
| security_groups | [{u'name': u'default'}] |
| status | BUILD |
| updated | 2017-02-10T07:14:04Z |
| user_id | f5291b4b11024ecc9f1938f8f895923f |
+--------------------------------------+-------------------------------------------------------------------------------------------------------+

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/432884

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/432884
Committed: https://git.openstack.org/cgit/openstack/ooi/commit/?id=a8cfcb58e8cda3e36cba5569b051689ced612925
Submitter: Jenkins
Branch: master

commit a8cfcb58e8cda3e36cba5569b051689ced612925
Author: Enol Fernandez <email address hidden>
Date: Mon Feb 13 07:09:55 2017 +0000

    Do not crash on volume attachments without device

    Sometimes OpenStack does not return any device in the attached volumes, this
    change avoids a KeyError when not defined.

    Change-Id: If96fa02a7d6fd93e31667b2481943c6294173f72
    Closes-Bug: #1663491