NSX|V+V3: Fix QoS peak bandwidth calculation

The NSX backend supports configuration of Peak Bandwidth, but if it is the same
as the average bandwidth, bursts are not allowed.
To fix this, we added a new configuration multiplier that will be used to
calculate the peak bw out of the neutron max bw.

Change-Id: I38ca66dfccdf09aca2ea31015174f0615cf83656

vmware_nsx/common/config.py

@@ -111,6 +111,12 @@ base_opts = [
                       "does not want to deploy a service node). In order to "
                       "leverage distributed routers, replication_mode should "
                       "be set to 'service'.")),
+    #TODO(asarfaty): add min/max values to FloatOpt. This value should be > 1
+    cfg.FloatOpt('qos_peak_bw_multiplier', default=2.0,
+                 help=_("The QoS rules peak bandwidth value will be the "
+                        "configured maximum bandwidth of the QoS rule, "
+                        "multiplied by this value. Value must be bigger than"
+                        " 1")),
 ]
 
 sync_opts = [

vmware_nsx/services/qos/README.rst

@@ -27,4 +27,9 @@
     [qos]
     notification_drivers = vmware_nsxv3_message_queue
 
-5. run ``stack.sh``
+5. Optional: Update the nsx qos_peak_bw_multiplier in nsx.ini (default value is 2.0)::
+
+    [NSX]
+    qos_peak_bw_multiplier = <i.e 10.0>
+
+6. run ``stack.sh``

vmware_nsx/services/qos/nsx_v/utils.py

@@ -21,6 +21,7 @@ from neutron.objects.qos import policy as qos_policy
 from neutron.plugins.common import constants
 from neutron.services.qos import qos_consts
 
+from oslo_config import cfg
 from oslo_log import log as logging
 
 from vmware_nsx.db import db as nsx_db
@@ -74,10 +75,12 @@ class NsxVQosRule(object):
                         self.bandwidthEnabled = True
                         # averageBandwidth: kbps (neutron) -> bps (nsxv)
                         self.averageBandwidth = rule_obj['max_kbps'] * 1024
-                        # peakBandwidth: the same as the average value
+                        # peakBandwidth: a Multiplying on the average BW
                         # because the neutron qos configuration supports
                         # only 1 value
-                        self.peakBandwidth = self.averageBandwidth
+                        self.peakBandwidth = int(
+                            self.averageBandwidth *
+                            cfg.CONF.NSX.qos_peak_bw_multiplier)
                         # burstSize: kbps (neutron) -> Bytes (nsxv)
                         self.burstSize = rule_obj['max_burst_kbps'] * 128
                     if rule_obj['type'] == qos_consts.RULE_TYPE_DSCP_MARKING:

vmware_nsx/services/qos/nsx_v3/utils.py

@@ -19,6 +19,7 @@ from neutron import context as n_context
 from neutron.objects.qos import policy as qos_policy
 from neutron.services.qos import qos_consts
 from neutron_lib.api import validators
+from oslo_config import cfg
 from oslo_log import log as logging
 
 from vmware_nsx._i18n import _, _LW
@@ -136,9 +137,13 @@ class QosNotificationsHandler(object):
             burst_size = int(bw_rule.max_burst_kbps) * 128
 
             # translate kbps -> Mbps
-            peak_bandwidth = int(float(bw_rule.max_kbps) / 1024)
-            # neutron QoS does not support this parameter
-            average_bandwidth = peak_bandwidth
+            average_bandwidth = int(float(bw_rule.max_kbps) / 1024)
+
+            # peakBandwidth: a Multiplying on the average BW
+            # because the neutron qos configuration supports
+            # only 1 value
+            peak_bandwidth = int(average_bandwidth *
+                                 cfg.CONF.NSX.qos_peak_bw_multiplier)
         else:
             shaping_enabled = False
             burst_size = None

vmware_nsx/tests/unit/services/qos/test_nsxv3_notification.py

@@ -83,6 +83,8 @@ class TestQosNsxV3Notification(nsxlib_testcase.NsxClientTestCase,
         mock.patch.object(nsx_db, 'get_switch_profile_by_qos_policy',
             return_value=self.fake_profile_id).start()
 
+        self.peak_bw_multiplier = cfg.CONF.NSX.qos_peak_bw_multiplier
+
     @mock.patch(
         'neutron.objects.rbac_db.RbacNeutronDbObjectMixin'
         '.create_rbac_policy')
@@ -156,11 +158,12 @@ class TestQosNsxV3Notification(nsxlib_testcase.NsxClientTestCase,
                     rule_dict = self.rule_data['bandwidth_limit_rule']
                     expected_bw = rule_dict['max_kbps'] // 1024
                     expected_burst = rule_dict['max_burst_kbps'] * 128
+                    expected_peak = int(expected_bw * self.peak_bw_multiplier)
                     update_profile.assert_called_once_with(
                         self.fake_profile_id,
                         average_bandwidth=expected_bw,
                         burst_size=expected_burst,
-                        peak_bandwidth=expected_bw,
+                        peak_bandwidth=expected_peak,
                         shaping_enabled=True,
                         qos_marking='trusted',
                         dscp=0
@@ -196,11 +199,12 @@ class TestQosNsxV3Notification(nsxlib_testcase.NsxClientTestCase,
                     rule_dict = rule_data['bandwidth_limit_rule']
                     expected_bw = qos_utils.MAX_KBPS_MIN_VALUE / 1024
                     expected_burst = rule_dict['max_burst_kbps'] * 128
+                    expected_peak = int(expected_bw * self.peak_bw_multiplier)
                     update_profile.assert_called_once_with(
                         self.fake_profile_id,
                         average_bandwidth=expected_bw,
                         burst_size=expected_burst,
-                        peak_bandwidth=expected_bw,
+                        peak_bandwidth=expected_peak,
                         shaping_enabled=True,
                         dscp=0,
                         qos_marking='trusted'