Cleanup soft (anti)affinity weight multiplier options

This resolves the TODO from Ocata change:

  I8871b628f0ab892830ceeede68db16948cb293c8

By adding a min=0.0 value to the soft affinity
weight multiplier configuration options.

It also removes the deprecated [DEFAULT] group
alias from Ocata change:

  I3f48e52815e80c99612bcd10cb53331a8c995fc3

Change-Id: I79e191010adbc0ec0ed02c9d589106debbf90ea8

doc/source/admin/configuration/schedulers.rst

@@ -871,16 +871,14 @@ Hosts and cells are weighted based on the following options in the
      - ``io_ops_weight_multiplier``
      - Multiplier used for weighing host I/O operations. A negative value means
        a preference to choose light workload compute hosts.
-   * - [DEFAULT]
+   * - [filter_scheduler]
      - ``soft_affinity_weight_multiplier``
      - Multiplier used for weighing hosts for group soft-affinity.  Only a
-       positive value is meaningful. Negative means that the behavior will
-       change to the opposite, which is soft-anti-affinity.
-   * - [DEFAULT]
+       positive value is allowed.
+   * - [filter_scheduler]
      - ``soft_anti_affinity_weight_multiplier``
      - Multiplier used for weighing hosts for group soft-anti-affinity.  Only a
-       positive value is meaningful. Negative means that the behavior will
-       change to the opposite, which is soft-affinity.
+       positive value is allowed.
    * - [filter_scheduler]
      - ``build_failure_weight_multiplier``
      - Multiplier used for weighing hosts which have recent build failures. A

doc/source/user/filter-scheduler.rst

@@ -443,15 +443,12 @@ The Filter Scheduler weighs hosts based on the config option
 * |ServerGroupSoftAffinityWeigher| The weigher can compute the weight based
   on the number of instances that run on the same server group. The largest
   weight defines the preferred host for the new instance. For the multiplier
-  only a positive value is meaningful for the calculation as a negative value
-  would mean that the affinity weigher would prefer non collocating placement.
+  only a positive value is allowed for the calculation.
 
 * |ServerGroupSoftAntiAffinityWeigher| The weigher can compute the weight based
   on the number of instances that run on the same server group as a negative
   value. The largest weight defines the preferred host for the new instance.
-  For the multiplier only a positive value is meaningful for the calculation as
-  a negative value would mean that the anti-affinity weigher would prefer
-  collocating placement.
+  For the multiplier only a positive value is allowed for the calculation.
 
 * |BuildFailureWeigher| Weigh hosts by the number of recent failed boot attempts.
   It considers the build failure counter and can negatively weigh hosts with

nova/conf/scheduler.py

@@ -467,10 +467,9 @@ Possible values:
 * A positive integer or float value, where the value corresponds to the
   multiplier ratio for this weigher.
 """),
-    # TODO(sfinucan): Add 'min' parameter and remove warning in 'affinity.py'
     cfg.FloatOpt("soft_affinity_weight_multiplier",
         default=1.0,
-        deprecated_group="DEFAULT",
+        min=0.0,
         help="""
 Multiplier used for weighing hosts for group soft-affinity.
 
@@ -483,7 +482,7 @@ Possible values:
     cfg.FloatOpt(
         "soft_anti_affinity_weight_multiplier",
         default=1.0,
-        deprecated_group="DEFAULT",
+        min=0.0,
         help="""
 Multiplier used for weighing hosts for group soft-anti-affinity.
 

nova/scheduler/weights/affinity.py

@@ -54,40 +54,15 @@ class _SoftAffinityWeigherBase(weights.BaseHostWeigher):
 
 class ServerGroupSoftAffinityWeigher(_SoftAffinityWeigherBase):
     policy_name = 'soft-affinity'
-    warning_sent = False
 
     def weight_multiplier(self):
-        if (CONF.filter_scheduler.soft_affinity_weight_multiplier < 0 and
-                not self.warning_sent):
-            LOG.warning('For the soft_affinity_weight_multiplier only a '
-                        'positive value is meaningful as a negative value '
-                        'would mean that the affinity weigher would '
-                        'prefer non-collocating placement. Future '
-                        'versions of nova will restrict the config '
-                        'option to values >=0. Update your configuration '
-                        'file to mitigate future upgrade issues.')
-            self.warning_sent = True
-
         return CONF.filter_scheduler.soft_affinity_weight_multiplier
 
 
 class ServerGroupSoftAntiAffinityWeigher(_SoftAffinityWeigherBase):
     policy_name = 'soft-anti-affinity'
-    warning_sent = False
 
     def weight_multiplier(self):
-        if (CONF.filter_scheduler.soft_anti_affinity_weight_multiplier < 0 and
-                not self.warning_sent):
-            LOG.warning('For the soft_anti_affinity_weight_multiplier '
-                        'only a positive value is meaningful as a '
-                        'negative value would mean that the anti-affinity '
-                        'weigher would prefer collocating placement. '
-                        'Future versions of nova will restrict the '
-                        'config option to values >=0. Update your '
-                        'configuration file to mitigate future upgrade '
-                        'issues.')
-            self.warning_sent = True
-
         return CONF.filter_scheduler.soft_anti_affinity_weight_multiplier
 
     def _weigh_object(self, host_state, request_spec):

nova/tests/unit/scheduler/weights/test_weights_affinity.py

@@ -104,19 +104,6 @@ class SoftAffinityWeigherTestCase(SoftWeigherTestBase):
                       expected_weight=2.0,
                       expected_host='host2')
 
-    @mock.patch.object(affinity, 'LOG')
-    def test_soft_affinity_weight_multiplier_negative_value(self, mock_log):
-        self.flags(soft_affinity_weight_multiplier=-1.0,
-                   group='filter_scheduler')
-        self._do_test(policy='soft-affinity',
-                      expected_weight=0.0,
-                      expected_host='host3')
-        # call twice and assert that only one warning is emitted
-        self._do_test(policy='soft-affinity',
-                      expected_weight=0.0,
-                      expected_host='host3')
-        self.assertEqual(1, mock_log.warning.call_count)
-
 
 class SoftAntiAffinityWeigherTestCase(SoftWeigherTestBase):
 
@@ -143,17 +130,3 @@ class SoftAntiAffinityWeigherTestCase(SoftWeigherTestBase):
         self._do_test(policy='soft-anti-affinity',
                       expected_weight=2.0,
                       expected_host='host3')
-
-    @mock.patch.object(affinity, 'LOG')
-    def test_soft_anti_affinity_weight_multiplier_negative_value(self,
-                                                                 mock_log):
-        self.flags(soft_anti_affinity_weight_multiplier=-1.0,
-                   group='filter_scheduler')
-        self._do_test(policy='soft-anti-affinity',
-                      expected_weight=0.0,
-                      expected_host='host2')
-        # call twice and assert that only one warning is emitted
-        self._do_test(policy='soft-anti-affinity',
-                      expected_weight=0.0,
-                      expected_host='host2')
-        self.assertEqual(1, mock_log.warning.call_count)

releasenotes/notes/stein-affinity-weight-multiplier-cleanup-fed9ec25660befd3.yaml

@@ -0,0 +1,8 @@
+---
+upgrade:
+  - |
+    The ``[filter_scheduler]/soft_affinity_weight_multiplier`` and
+    ``[filter_scheduler]/soft_anti_affinity_weight_multiplier`` configuration
+    options now have a hard minimum value of 0.0. Also, the deprecated alias
+    to the ``[DEFAULT]`` group has been removed so the options must appear in
+    the ``[filter_scheduler]`` group.