On 12/20/2018 8:02 AM, Bence Romsics wrote:
I like the idea of a feature flag, however technically in neutron we don't directly control the list of extensions loaded. Instead what we control (through configuration) is the list of service plugins loaded. The 'resource_request' extension is implemented by the 'qos' service plugin. But the 'qos' service plugin implements other API extensions and features too. A cloud admin may want to use these other features of the 'qos' service plugin, but not the guaranteed minimum bandwidth. Therefore I'd suggest adding the feature flag to nova to keep this usage possible.
Can't the resource_request part of this be controlled via policy rules or something similar? If neutron were using microversions, users would have to opt into this new QoS bandwidth behavior and nova, as a client, would also have to request that information about each port from neutron to know if it's even available in the neutron server version they are talking to. Anyway, microversions aside, it's not clear to me why a neutron API extension doesn't control if this new field is added to the port resource response? Barring that, are policy rules something that could be used for deployers could decide which users can use this feature while it's being rolled out? -- Thanks, Matt