[QoS][SR-IOV] Minimum BW dataplane enforcement fails if NIC does not support min_tx_rate

[Rodolfo Alonso]

If a network interface does not support "min_tx_rate" parameter, the QoS minimum BW rule will fail in SR-IOV.

This can be tested manually in a SR-IOV network card using this command:
  # ip link set ens785f1 vf 0 min_tx_rate 0

That command will fail if the driver does not support "min_tx_rate".
  # ip l set dev enp5s0f0 vf 2 max_tx_rate 8000
  # ip l set dev enp5s0f0 vf 2 min_tx_rate 6000
    RTNETLINK answers: Invalid argument

In the SR-IOV agent, the QoS enforcement will fail with the following error: http://paste.openstack.org/show/803441/

This behaviour depends on the NIC driver, not the API (ip-link or Pyroute2). My recommendation here is to catch this exception, log an error and exit the method gracefully.

BZ reference: https://bugzilla.redhat.com/show_bug.cgi?id=1937432

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Patch: https://review.opendev.org/c/openstack/neutron/+/779937

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 18.0.0.0rc1 release candidate.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 15.3.4 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 16.3.2 release.

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 17.1.2 release.