nova api returns 500 when resizing an instance with memory encryption enabled

[Takashi Kajinami]

Description
===========
When a user attempts to resize an instance with memory encryption enabled, API returns 500 error consistently.
Looking into nova-api.log, it seems the issue is caused by a mechanism similar to https://bugs.launchpad.net/nova/+bug/2041511 .

Steps to reproduce
==================
* Create an image with hw_mem_encryption=True
 $ openstack image create encrypted ...
 $ openstack image set encrypted --property hw_mem_encryption=True

* Create an instance
 $ openstack server create testinstance --image encrypted --flavor flavor1 ...

* Resize the instance
 $ openstack server resize testinstance --flavor flavor2

Expected result
===============
Instance resize is accepted and processed by nova, without errors

Actual result
=============
Nova api returns 500 error and does not accept the request

Environment
===========

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

Ubuntu 22.04 and UCA bobcat.

# dpkg -l | grep nova
ii nova-api 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - API frontend
ii nova-common 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - common files
ii nova-compute 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - compute node base
ii nova-compute-kvm 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - compute node (KVM)
ii nova-compute-libvirt 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - compute node libvirt support
ii nova-conductor 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - conductor service
ii nova-novncproxy 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - NoVNC proxy
ii nova-scheduler 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute - virtual machine scheduler
ii python3-nova 3:28.0.0-0ubuntu1~cloud0 all OpenStack Compute Python 3 libraries
ii python3-novaclient 2:18.4.0-0ubuntu1~cloud0 all client library for OpenStack Compute API - 3.x

2. Which hypervisor did you use?
Libvirt + KVM

3. Which storage type did you use?
LVM

4. Which networking type did you use?
ml2 + ovs

Logs & Configs
==============
The following traceback is found in nova-api.log

```
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi [None req-20b9b69c-a792-45cd-8520-7e9cd3387c0d 838cd42e04884ddfa8ec4ac11e2f8818 baf003aa0202430a92edd003f98794a3 - - default default] Unexpected exception in API method: NotImplementedError: Cannot load 'id' in the base class
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi Traceback (most recent call last):
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/api/openstack/wsgi.py", line 658, in wrapped
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return f(*args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/api/validation/__init__.py", line 110, in wrapper
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return func(*args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/api/openstack/compute/servers.py", line 1146, in _action_resize
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi self._resize(req, id, flavor_ref, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/api/openstack/compute/servers.py", line 1060, in _resize
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi self.compute_api.resize(context, instance, flavor_id,
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 389, in inner
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return function(self, context, instance, *args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 374, in wrapper
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return func(self, context, instance, *args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 357, in wrapper
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return func(self, context, instance, *args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 242, in inner
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return function(self, context, instance, *args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 168, in inner
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return f(self, context, instance, *args, **kw)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 232, in wrapped
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi return function(self, context, instance, *args, **kwargs)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 4270, in resize
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi self._validate_flavor_image_nostatus(
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 830, in _validate_flavor_image_nostatus
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi API._validate_flavor_image_numa_pci(
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/compute/api.py", line 880, in _validate_flavor_image_numa_pci
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi hardware.get_mem_encryption_constraint(flavor, image_meta)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/nova/virt/hardware.py", line 1195, in get_mem_encryption_constraint
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi image_meta.id)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/oslo_versionedobjects/base.py", line 67, in getter
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi self.obj_load_attr(name)
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi File "/usr/lib/python3/dist-packages/oslo_versionedobjects/base.py", line 600, in obj_load_attr
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi raise NotImplementedError(
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi NotImplementedError: Cannot load 'id' in the base class
2023-12-26 08:02:19.371 30791 ERROR nova.api.openstack.wsgi
```

[Jie Song (songjie-cmss)]

In nova/compute/api.py resize() function, `image = utils.get_image_from_system_metadata(instance.system_metadata)` will lead to `image` has no `id` key.

Therefore, when calling `self._validate_flavor_image_nostatus()→API._validate_flavor_image_numa_pci()→hardware.get_mem_encryption_constraint()`, using `image_meta.id` will will cause an error.

See https://bugs.launchpad.net/nova/+bug/2041511, the similar issue.

[OpenStack Infra (hudson-openstack)]

Related fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/nova/+/904197