nova/releasenotes/notes/remove-os-pci-api-4fcbf5fdf11c4c63.yaml
Matt Riedemann 75a7e6fc7d Remove unused os-pci API
The os-pci API was never part of the v2.0 API and was added
to the v3 API, but when the v3 API turned into the v2.1 API
which is backward compatible with the v2.0 API, the os-pci
API was removed from v2.1. The original intent was to enable
it in a microversion but that never happened.

We should just delete this API since it has a number of issues
anyway:

1. It's not documented (which makes sense since it's not enabled).
2. The PciHypervisorController just takes the compute_nodes.pci_stats
   dict and dumps it to json out of the REST API with no control over
   the keys in the response. That means if we ever change the fields
   in the PciDevicePool object, we implicitly introduce a backward
   incompatible change in the REST API.
3. We don't want to be reporting host stats out of the API [1].
4. To make the os-hypervisors extension work in a multi-cell environment
   we'd have to add uuids to the PciDevices model and change the API to
   return and take in uuids to identify the devices for GET requests.
5. And last but not least, no one has asked for this in over two years.

As a result of removing this API we can also remove the join on the
pci_devices table when showing details about an instance or listing
instances, which were added years ago because of the PciServerController:

Id3c8a0b187e399ce2acecd4aaa37ac95e731d46c

Id3e60c3c56c2eb4209e8aca8a2c26881ca86b435

[1] https://docs.openstack.org/developer/nova/policies.html?#metrics-gathering

Closes-Bug: #1426241
Closes-Bug: #1673869

Change-Id: I9099744264eeec175672d10d04da69648dec1a9d
2017-04-18 23:47:40 -04:00

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YAML

---
other:
- |
The disabled ``os-pci`` API has been removed. This API was originally added
to the v3 API which over time finally became the v2.1 API and the initial
microversion is backward compatible with the v2.0 API, where the
``os-pci`` extension did not exist. The ``os-pci`` API was never enabled
as a microversion in the v2.1 API and at this time no longer aligns with
Nova strategically and is therefore just technical debt, so it has been
removed. Since it was never enabled or exposed out of the compute REST API
endpoint there was no deprecation period for this.