nova boot fails while using bootable cinder volume which was created from an image created from a volume

[LiJun Zhu]

Description
===========
nova boot fails while using bootable cinder volume as a backend when that cinder volume is created from a volume-based image.

A similar issue is https://bugzilla.redhat.com/show_bug.cgi?id=1414226.

Steps to reproduce
==================
1. Create a bootable volume.
[root@zhuljbj-mgt ~]# cinder list
+--------------------------------------+-----------+------------------+------+--------------------------------------------------------------------------------------+----------+--------------------------------------+
| ID | Status | Name | Size | Volume Type | Bootable | Attached to |
+--------------------------------------+-----------+------------------+------+--------------------------------------------------------------------------------------+----------+--------------------------------------+
| 5228a250-e541-434f-af7d-e583aed58c4c | available | zlj-vol | 10 | fl63 base template | true | |
+--------------------------------------+-----------+------------------+------+--------------------------------------------------------------------------------------+----------+--------------------------------------+

2. Create a glance image with the volume 'zlj-vol'
[root@zhuljbj-mgt ~]# glance image-list
+--------------------------------------+-----------------+
| ID | Name |
+--------------------------------------+-----------------+
| 3f3eff5f-33b6-490f-ae08-f4dbc048b178 | zlj-vol-img |
+--------------------------------------+-----------------+

[root@zhuljbj-mgt ~]# glance image-show 3f3eff5f-33b6-490f-ae08-f4dbc048b178
+----------------------+----------------------------------------------------------------------------------+
| Property | Value |
+----------------------+----------------------------------------------------------------------------------+
| architecture | s390x |
| base_image_ref | |
| bdm_v2 | True |
| block_device_mapping | [{"guest_format":null,"boot_index":0,"no_device":null,"image_id":null,"volume_id |
| | ":"5228a250-e541-434f-af7d-e583aed58c4c","volume_type":"fl63 base template","dis |
| | k_bus":null,"device_name":"/dev/vda","volume_size":10,"source_type":"volume","sn |
| | apshot_id":null,"destination_type":"volume","delete_on_termination":false}] |
| checksum | d41d8cd98f00b204e9800998ecf8427e |
| container_format | bare |
| created_at | 2024-04-11T09:06:27Z |
| disk_format | raw |
| disk_type | SCSI |
| hypervisor_type | zvm |
| id | 3f3eff5f-33b6-490f-ae08-f4dbc048b178 |
| min_disk | 0 |
| min_ram | 0 |
| name | zlj-vol-img |
| os_distro | Rhel9 |
| os_hash_algo | sha512 |
| os_hash_value | cf83e1357eefb8bdf1542850d66d8007d620e4050b5715dc83f4a921d36ce9ce47d0d13c5d85f2b0 |
| | ff8318d2877eec2f63b931bd47417a81a538327af927da3e |
| os_hidden | False |
| owner | 6f9ee43b492f40efa3506a9f45a59665 |
| protected | False |
| secure_execution | False |
| size | 0 |
| status | active |
| tags | [] |
| updated_at | 2024-04-11T09:06:28Z |
| virtual_size | Not available |
| visibility | private |
+----------------------+----------------------------------------------------------------------------------+

3. Create a bootable cinder volume using the image
[root@zhuljbj-mgt ~]# cinder create --image zlj-vol-img --display-name zlj-vt-from-img 20
+------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+
| Property | Value |
+------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+
| attachments | [] |
| availability_zone | Default_Group |
| bootable | false |
| consistencygroup_id | None |
| created_at | 2024-04-11T09:07:02.000000 |
| description | None |
| encrypted | False |
| group_id | None |
| health_status | {'id': '72aa9955-a0db-4352-b702-9a93e120de5f', 'health_value': 'PENDING', 'updated_at': '2024-04-11T09:07:02.842989', 'value_reason': 'PENDING'} |
| host | None |
| id | 72aa9955-a0db-4352-b702-9a93e120de5f |
| metadata | {} |
| migration_status | None |
| multiattach | False |
| name | zlj-vt-from-img |
| os-vol-host-attr:host | None |
| os-vol-tenant-attr:tenant_id | 6f9ee43b492f40efa3506a9f45a59665 |
| provider_id | None |
| replication_status | None |
| service_uuid | None |
| shared_targets | True |
| size | 20 |
| snapshot_id | None |
| source_volid | None |
| status | creating |
| updated_at | None |
| user_id | 0688b01e6439ca32d698d20789d52169126fb41fb1a4ddafcebb97d854e836c9 |
| volume_type | None |
+------------------------------+--------------------------------------------------------------------------------------------------------------------------------------------------+

4. Boot a vm instance using the bootable cinder volume
[root@zhuljbj-mgt ~]# nova boot --poll --flavor tiny --nic net-name=zvmnet --block-device-mapping vda=72aa9955-a0db-4352-b702-9a93e120de5f:::0 inst4
nova CLI is deprecated and will be a removed in a future release
ERROR (BadRequest): Invalid image metadata. Error: A list is required in field img_block_device_mapping, not a str (HTTP 400) (Request-ID: req-0b66590b-e421-4b58-b1cf-62c6199470ba)

Expected result
===============
nova boot command should complete successfully without any errors.

Actual result
=============
Below error is reported.
ERROR (BadRequest): Invalid image metadata. Error: A list is required in field img_block_device_mapping, not a str (HTTP 400) (Request-ID: req-0b66590b-e421-4b58-b1cf-62c6199470ba)

Environment
===========
1. Exact version of OpenStack you are running. See the following
  list for all releases: http://docs.openstack.org/releases/

[root@zhuljbj-mgt ~]# rpm -qa | grep nova
openstack-nova-api-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-common-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-27.0.0-122.0.202404060250.ibm.el8.noarch
python3-nova-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-conductor-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-scheduler-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-compute-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-novncproxy-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-compute-prereqs-2013.1-122.0.202401180005.ibm.el8.s390x
python3-novaclient-18.3.0-122.0.202401181402.ibm.el8.noarch
openstack-nova-network-27.0.0-122.0.202404060250.ibm.el8.noarch
openstack-nova-console-27.0.0-122.0.202404060250.ibm.el8.noarch

2. Which hypervisor did you use?
   z/VM

2. Which storage type did you use?
   IBM Flashsystem

3. Which networking type did you use?
   nova-network

Logs & Configs
==============