[OVN] FIP QoS and router QoS have the same priority

[Rodolfo Alonso]

The default QoS priority for an OVN QoS rule is "OVN_QOS_DEFAULT_RULE_PRIORITY = 2002" [1].

A port connected to a router can have up to 3 QoS rules applied:
* The port QoS
* The router QoS
* The FIP QoS (when a FIP is assigned).

NOTE: the priority of the port QoS will be handled in other bug.

The problem is how to handle the priority of the router QoS and FIP QoS. Both rules are matching the egress/ingress gateway LRP (the FIP is also matching the IP address and the CR port, if present). According to [2], "if two QoS rules with the same priority both match, then the one actually applied to a packet is undefined". Because of that, we need to increase the priority of the FIP rules that will superseed the router QoS one.

[1]https://github.com/openstack/neutron/blob/aa4ab837a0390b1c1c3039fe0b196361178f5749/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/extensions/qos.py#L35
[2]https://www.ovn.org/support/dist-docs/ovn-nb.5.html

Jira reference: https://issues.redhat.com/browse/OSPRH-16265

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/c/openstack/neutron/+/948894

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/2025.1
Review: https://review.opendev.org/c/openstack/neutron/+/949312

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/948894
Committed: https://opendev.org/openstack/neutron/commit/012327bb4dfa8ab1817fb03cac530a8daa109f98
Submitter: "Zuul (22348)"
Branch: master

commit 012327bb4dfa8ab1817fb03cac530a8daa109f98
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Tue May 6 10:08:36 2025 +0000

    [OVN] Change the OVN QoS rule priority for floating IPs

    The OVN QoS rules for router and floating IPs have the same priority
    and similar matches. For the router rule, the match is the gateway
    Logical_Router_Port, that always matches the traffic for the floating IP
    too. If two QoS rules with the same priority match, the selected one
    is not defined [1].

    This patch is increasing the priority of the floating IP OVN QoS rules
    to match before the router QoS rules.

    NOTE: the floating IP QoS rules are deleted matching the QoS external_ids
    [2], instead of creating the same QoS rule, thus the priority is not
    needed for the deletion.

    [1]https://www.ovn.org/support/dist-docs/ovn-nb.5.html
    [2]https://github.com/openstack/neutron/blob/123bd115f3b65ba09560685ad6cf68c6934a6535/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/extensions/qos.py#L451-L456

    Closes-Bug: #2110018
    Change-Id: If01a8783ac998b2a1f1249ab6f555dd1a5148ea8

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/c/openstack/neutron/+/949312
Committed: https://opendev.org/openstack/neutron/commit/99369551687189b9791d57e67734bddb8a1d23d5
Submitter: "Zuul (22348)"
Branch: stable/2025.1

commit 99369551687189b9791d57e67734bddb8a1d23d5
Author: Rodolfo Alonso Hernandez <email address hidden>
Date: Tue May 6 10:08:36 2025 +0000

    [OVN] Change the OVN QoS rule priority for floating IPs

    The OVN QoS rules for router and floating IPs have the same priority
    and similar matches. For the router rule, the match is the gateway
    Logical_Router_Port, that always matches the traffic for the floating IP
    too. If two QoS rules with the same priority match, the selected one
    is not defined [1].

    This patch is increasing the priority of the floating IP OVN QoS rules
    to match before the router QoS rules.

    NOTE: the floating IP QoS rules are deleted matching the QoS external_ids
    [2], instead of creating the same QoS rule, thus the priority is not
    needed for the deletion.

    [1]https://www.ovn.org/support/dist-docs/ovn-nb.5.html
    [2]https://github.com/openstack/neutron/blob/123bd115f3b65ba09560685ad6cf68c6934a6535/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/extensions/qos.py#L451-L456

    Closes-Bug: #2110018
    Change-Id: If01a8783ac998b2a1f1249ab6f555dd1a5148ea8
    (cherry picked from commit 012327bb4dfa8ab1817fb03cac530a8daa109f98)

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 26.0.1 Epoxy release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 27.0.0.0b1 Flamingo development milestone.