Merge "Deprecate filters that have been replaced by placement filters"

Author: Zuul

doc/source/admin/availability-zones.rst

@@ -65,7 +65,7 @@ placement aggregates that match the membership and UUID of nova host aggregates
 that you assign as availability zones. The same key in aggregate metadata used
 by the `AvailabilityZoneFilter` filter controls this function, and is enabled by
 setting :oslo.config:option:`scheduler.query_placement_for_availability_zone`
-to ``True``.
+to ``True``. As of 24.0.0 (Xena), this is the default.
 
 .. code-block:: console
 
@@ -102,11 +102,9 @@ to ``True``.
 
   $ openstack --os-placement-api-version=1.2 resource provider aggregate set --aggregate 019e2189-31b3-49e1-aff2-b220ebd91c24 815a5634-86fb-4e1e-8824-8a631fee3e06
 
-With the above configuration, the `AvailabilityZoneFilter` filter can be
-disabled in :oslo.config:option:`filter_scheduler.enabled_filters` while
-retaining proper behavior (and doing so with the higher performance of
-placement's implementation).
-
+Without the above configuration, the `AvailabilityZoneFilter` filter must be
+enabled in :oslo.config:option:`filter_scheduler.enabled_filters` to retain
+proper behavior.
 
 Implications for moving servers
 -------------------------------

doc/source/admin/configuration/schedulers.rst

@@ -18,7 +18,7 @@ Compute is configured with the following default scheduler options in the
 
    [filter_scheduler]
    available_filters = nova.scheduler.filters.all_filters
-   enabled_filters = AvailabilityZoneFilter, ComputeFilter, ComputeCapabilitiesFilter, ImagePropertiesFilter, ServerGroupAntiAffinityFilter, ServerGroupAffinityFilter
+   enabled_filters = ComputeFilter, ComputeCapabilitiesFilter, ImagePropertiesFilter, ServerGroupAntiAffinityFilter, ServerGroupAffinityFilter
 
 By default, the scheduler ``driver`` is configured as a filter scheduler, as
 described in the next section. In the default configuration, this scheduler
@@ -341,8 +341,12 @@ This is a no-op filter. It does not eliminate any of the available hosts.
 AvailabilityZoneFilter
 ----------------------
 
-Filters hosts by availability zone. You must enable this filter for the
-scheduler to respect availability zones in requests.
+.. deprecated:: 24.0.0 (Xena)
+
+   The functionality of this filter has been replaced by
+   :ref:`availability-zones-with-placement`.
+
+Filters hosts by availability zone.
 
 Refer to :doc:`/admin/availability-zones` for more information.
 

nova/conf/scheduler.py

@@ -150,7 +150,18 @@
 - ``[scheduler] placement_aggregate_required_for_tenants``
 """),
     cfg.BoolOpt("query_placement_for_availability_zone",
-        default=False,
+        default=True,
+        deprecated_for_removal=True,
+        deprecated_since='24.0.0',
+        deprecated_reason="""
+Since the introduction of placement pre-filters in 18.0.0 (Rocky), we have
+supported tracking Availability Zones either natively in placement or using the
+legacy ``AvailabilityZoneFilter`` scheduler filter. In 24.0.0 (Xena), the
+filter-based approach has been deprecated for removal in favor of the
+placement-based approach. As a result, this config option has also been
+deprecated and will be removed when the ``AvailabilityZoneFilter`` filter is
+removed.
+""",
         help="""
 Use placement to determine availability zones.
 
@@ -164,8 +175,9 @@
 found, or that aggregate does not match one in placement, the result will
 be the same as not finding any suitable hosts.
 
-Note that if you enable this flag, you can disable the (less efficient)
-AvailabilityZoneFilter in the scheduler.
+Note that if you disable this flag, you **must** enable the (less efficient)
+``AvailabilityZoneFilter`` in the scheduler in order to availability zones to
+work correctly.
 
 Possible values:
 
@@ -355,7 +367,6 @@
         # Tempest's scheduler_enabled_filters to keep the default values in
         # sync.
         default=[
-            "AvailabilityZoneFilter",
             "ComputeFilter",
             "ComputeCapabilitiesFilter",
             "ImagePropertiesFilter",

nova/scheduler/filters/availability_zone_filter.py

@@ -37,6 +37,21 @@ class AvailabilityZoneFilter(filters.BaseHostFilter):
 
     RUN_ON_REBUILD = False
 
+    def __init__(self):
+        super().__init__()
+        if CONF.scheduler.query_placement_for_availability_zone:
+            LOG.warning(
+                "The 'AvailabilityZoneFilter' is deprecated since the 24.0.0 "
+                "(Xena) release. Since the 18.0.0 (Rocky) release, nova "
+                "has supported mapping AZs to placement aggregates. "
+                "The feature is enabled by the "
+                "'query_placement_for_availability_zone' config option and "
+                "is now enabled by default. As such, the "
+                "'AvailabilityZoneFilter' is no longer required. Nova is "
+                "currently configured to use both placement and the "
+                "AvailabilityZoneFilter for AZ enforcement."
+            )
+
     def host_passes(self, host_state, spec_obj):
         availability_zone = spec_obj.availability_zone
 

nova/tests/functional/test_aggregates.py

@@ -444,13 +444,6 @@ def setUp(self):
         # Use custom weigher to make sure that we have a predictable
         # scheduling sort order.
         self.useFixture(nova_fixtures.HostNameWeigherFixture())
-
-        # NOTE(danms): Do this before calling setUp() so that
-        # the scheduler service that is started sees the new value
-        filters = CONF.filter_scheduler.enabled_filters
-        filters.remove('AvailabilityZoneFilter')
-        self.flags(enabled_filters=filters, group='filter_scheduler')
-
         super(AvailabilityZoneFilterTest, self).setUp()
 
     def test_filter_with_az(self):
@@ -729,7 +722,6 @@ def setUp(self):
         # NOTE(danms): Do this before calling setUp() so that
         # the scheduler service that is started sees the new value
         filters = CONF.filter_scheduler.enabled_filters
-        filters.remove('AvailabilityZoneFilter')
 
         # NOTE(shilpasd): To test `isolate_aggregates` request filter, removed
         # following filters which also filters hosts based on aggregate

releasenotes/notes/deprecate-AZ-filter-28406abc0135c1c3.yaml

@@ -0,0 +1,18 @@
+---
+deprecations:
+  - |
+    The ``AvailabilityZoneFilter`` scheduler filters is now deprecated
+    for removal in a future release. The functionality of the
+    ``AvailabilityZoneFilter`` has been replaced by the
+    ``map_az_to_placement_aggregate`` pre-filter which was introduced in
+    18.0.0 (Rocky). This pre-filter is now enabled by default and will be
+    mandatory in a future release.
+upgrades:
+  - |
+    The ``AvailabilityZoneFilter``  has been removed from the default
+    ``[scheduler] enabled_filters`` list. The ``AvailabilityZoneFilter``
+    is replaced by an optional placement pre-filter which is enabled by
+    ``[scheduler] query_placement_for_availability_zone``.
+    The pre-filter is now enabled by default. If you choose to disable the
+    AZ pre-filter, you will need to re-add ``AvailabilityZoneFilter`` to the
+    ``[scheduler] enabled_filters`` config value.