Comment 9 for bug 1639220

Hello:

@Miguel:
The behaviour you are asking for is currently present in the patch. A QoS policy belongs to a project and the "is_default" flags only affects to policies belonging to this project. That means you can have as many default QoS policies as projects you have in the deployment.

Take a look at QoSPolicy create function:
    def create(self):
        with db_api.autonested_transaction(self.obj_context.session):
            default_policy = obj_db_api.get_object(self.obj_context,
                                                   self.db_model,
                                                   project_id=self.project_id,
                                                   is_default=True)
            if default_policy and self.is_default:
                raise exceptions.QosDefaultPolicyFound(
                    policy_id=default_policy.id)
            super(QosPolicy, self).create()
            self.reload_rules()

The "default_policy" is filtered by "self.project_id".

A made some manual tests using the following patches:
- Neutron: https://review.openstack.org/#/c/428304/
- SDK: https://review.openstack.org/#/c/430363/
- OSclient: https://review.openstack.org/#/c/432260/

I created several QoS policies in several projects:
$ network qos policy create qos_demo_1 --default --project demo
$ network qos policy create qos_demo_2 --project demo
$ network qos policy create qos_alt_demo_1 --default --project alt_demo
$ network qos policy create qos_alt_demo_2 --project alt_demo

These commands are executed correctly. As you can see you have two default QoS policies. Then, I tried to set a second default rule in "demo" project:
$ network qos policy set qos_demo_2 --default
HttpException: Conflict, QoS policy 7ae20620-28c9-4fe7-b0f8-8015be4969ee is the default policy.
                                                 ^^ is qos_demo_1

Is this the behaviour you are expecting?

BTW, taking a look at the QoS policies, only admin can create/update/delete policies and rules. IMO we need to change this.

@Yamamoto:
This implementation doesn't provide this feature. If the default QoS policy is changed, it won't affect the existing ports. When a new port is created and a default QoS policy exists, the server will asign explicitly this QoS policy to this port.

In a nutshell: there is no propagation. This feature was meant to assign a QoS policy to new ports.