Instantiation failed with error: "ValueError: Field `associated_vnfc_cp_id' cannot be None"

[Masaki Oyama]

I failed to instantiate VNF including a scalable VDU designed not to be created in the initial state, with instantiateVnfRequest including information about a connection point binding to the VDU.

Details are as follows:

Conditions:
    - The VNF includes the VDU named as "VDU_1".
    - The VNF includes the CP named as "VDU1_CP0" binding to "VDU_1".
    - The number of instances of "VDU_1" can be 0 or 1, and it is designated as 0 by "instantiationLevelId" in instantiateVnfRequest.
    - instantiateVnfRequest includes the information about "VDU1_CP0"

VNFD:
 ```
 VDU_0:
      type: tosca.nodes.nfv.Vdu.Compute
      properties:
        name: VDU_0
        vdu_profile:
          min_number_of_instances: 1
          max_number_of_instances: 1

VDU_1:
      type: tosca.nodes.nfv.Vdu.Compute
      properties:
        name: VDU_1
        vdu_profile:
          min_number_of_instances: 0
          max_number_of_instances: 1

VDU0_CP0:
      type: tosca.nodes.nfv.VduCp
      properties: ...
      requirements:
        - virtual_binding: VDU_0

VDU1_CP0:
      type: tosca.nodes.nfv.VduCp
      properties: ...
      requirements:
        - virtual_binding: VDU_1

             .
             .
             .

- instantiation_levels:
    type: tosca.policies.nfv.InstantiationLevels
    properties:
      levels:
        r-node-min:
          scale_info:
            VDU_1:
              scale_level: 0
        r-node-max:
          scale_info:
            VDU_1:
              scale_level: 1
```

instantiateVnfRequest:
```
{
  "flavourId": "default",
  "instantiationLevelId": "r-node-min",
  "extVirtualLinks": [
    {
      "extCps": [
        {
          "cpConfig": [...],
          "cpdId": "VDU0_CP0"
        },
        {
          "cpConfig": [...],
          "cpdId": "VDU1_CP0"
        }
      ],
      "id": ...,
      "resourceId": ...
    },
  ],
  "vimConnectionInfo": ...,
  "additionalParams": ...,
}

Error:
```
ERROR oslo_messaging.rpc.server Exception during message handlingESC[00m: ValueError: Field `associated_vnfc_cp_id' cannot be None
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/dist-packages/oslo_messaging/rpc/server.py", line 165, in _process_incoming
    res = self.dispatcher.dispatch(message)
  File "/usr/local/lib/python3.8/dist-packages/oslo_messaging/rpc/dispatcher.py", line 309, in dispatch
    return self._do_dispatch(endpoint, method, ctxt, args)
  File "/usr/local/lib/python3.8/dist-packages/oslo_messaging/rpc/dispatcher.py", line 229, in _do_dispatch
    result = func(ctxt, **new_args)
  File "<decorator-gen-94>", line 2, in instantiate
  File "/opt/stack/tacker/tacker/common/coordination.py", line 143, in _synchronized
    return f(*a, **k)
  File "/opt/stack/tacker/tacker/conductor/conductor_server.py", line 1795, in instantiate
    self._instantiate_grant(context,
  File "/opt/stack/tacker/tacker/conductor/conductor_server.py", line 292, in decorated_function
    LOG.warning("Failed notification for vnf "
  File "/usr/local/lib/python3.8/dist-packages/oslo_utils/excutils.py", line 227, in __exit__
    self.force_reraise()
  File "/usr/local/lib/python3.8/dist-packages/oslo_utils/excutils.py", line 200, in force_reraise
    raise self.value
  File "/opt/stack/tacker/tacker/conductor/conductor_server.py", line 247, in decorated_function
    return function(self, context, *args, **kwargs)
  File "/opt/stack/tacker/tacker/conductor/conductor_server.py", line 1042, in _instantiate_grant
    vnflcm_utils._build_instantiated_vnf_info(vnfd_dict,
  File "/opt/stack/tacker/tacker/vnflcm/utils.py", line 545, in _build_instantiated_vnf_info
    inst_vnf_info.ext_cp_info = _set_ext_cp_info(instantiate_vnf_req,
  File "/opt/stack/tacker/tacker/vnflcm/utils.py", line 871, in _set_ext_cp_info
    ext_cp_info = objects.VnfExtCpInfo(
  File "/opt/stack/tacker/tacker/objects/base.py", line 57, in __init__
    super(TackerObject, self).__init__(context, **kwargs)
  File "/usr/local/lib/python3.8/dist-packages/oslo_versionedobjects/base.py", line 307, in __init__
    setattr(self, key, kwargs[key])
  File "/usr/local/lib/python3.8/dist-packages/oslo_versionedobjects/base.py", line 72, in setter
    field_value = field.coerce(self, name, value)
  File "/usr/local/lib/python3.8/dist-packages/oslo_versionedobjects/fields.py", line 202, in coerce
    return self._null(obj, attr)
  File "/usr/local/lib/python3.8/dist-packages/oslo_versionedobjects/fields.py", line 180, in _null
    raise ValueError(_("Field `%s' cannot be None") % attr)
ValueError: Field `associated_vnfc_cp_id' cannot be None
```

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/tacker/+/832224

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/tacker/+/832224
Committed: https://opendev.org/openstack/tacker/commit/98f7150fbb8b8abc677050e8d2e7627498c0f451
Submitter: "Zuul (22348)"
Branch: master

commit 98f7150fbb8b8abc677050e8d2e7627498c0f451
Author: Masaki Oyama <email address hidden>
Date: Mon Mar 7 12:57:11 2022 +0000

    Fix the definition of associated_vnfc_cp_id

    This patch will fix the definition of the field of
    associated_vnfc_cp_id. In the current implementation,
    the field of associated_vnfc_cp_id is not allowed to be null.
    But according to ETSI GS NFV-SOL 003 V3.6.1, the cardinality of
    associatedVnfcCpId is defined as "0..1",
    which means the associated_vnfc_cp_id is nullable.
    Therefore, this patch will fix it to comply with the standard of ETSI.

    Closes-Bug: #1948925
    Change-Id: I612835a7f8dd61c034b0f877d3356c901fc6027f

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tacker 7.0.0.0rc1 release candidate.