conf: Deprecate AggregateImagePropertiesIsolation opts

The 'AggregateImagePropertiesIsolation' scheduler filter allows users to
filter host aggregates by comparing aggregate and image metadata. The
'[filter_scheduler] aggregate_image_properties_isolation_namespace' and
'[filter_scheduler] aggregate_image_properties_isolation_separator'
options purport to allow users to specify a prefix to use for both the
aggregate and image metadata keys, allowing users to do e.g.:

  openstack image set --property customized.os_type=linux $IMAGE
  openstack aggregate set --property customized.os_type=windows $AGG1
  openstack aggregate set --property customized.os_type=linux $AGG2

However, as noted in change If7245a90711bd2ea13095ba26b9bc82ea3e17202,
this is no longer possible since we introduced the 'ImageMetaProps' o.vo
in Liberty and promptly lost the ability to see any non-o.vo image
metadata properties from glance.

There's a possibility, however slight, that some people are using
namespaces that match actual nova namespaces such as 'hw' and a
separator of '_', but those will continue to work just fine. Setting
anything else will result in the scheduler filter failing since the
image property will always appear to be absent. As a result, these could
be outright removed rather than deprecated. We choose to deprecate just
so people can see the warnings.

Change-Id: Ide763d75e42427a9df3673313895ef47b8727802
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

nova/conf/scheduler.py

@@ -844,11 +844,15 @@ Related options:
 * ``[filter_scheduler] isolated_images``
 * ``[filter_scheduler] isolated_hosts``
 """),
-    # TODO(stephenfin): Consider deprecating these next two options: they're
-    # effectively useless now that we don't support arbitrary image metadata
-    # properties
     cfg.StrOpt(
         "aggregate_image_properties_isolation_namespace",
+        deprecated_for_removal=True,
+        deprecated_since="33.0.0",
+        deprecated_reason="""
+It no longer possible to filter on arbitrary image metadata properties. Support
+for this was removed in 12.0.0 (Liberty). As a result, this option is no longer
+useful.
+""",
         help="""
 Image property namespace for use in the host aggregate.
 
@@ -873,6 +877,13 @@ Related options:
     cfg.StrOpt(
         "aggregate_image_properties_isolation_separator",
         default=".",
+        deprecated_for_removal=True,
+        deprecated_since="33.0.0",
+        deprecated_reason="""
+It no longer possible to filter on arbitrary image metadata properties. Support
+for this was removed in 12.0.0 (Liberty). As a result, this option is no longer
+useful.
+""",
         help="""
 Separator character(s) for image property namespace and name.
 

nova/scheduler/filters/aggregate_image_properties_isolation.py

@@ -15,7 +15,6 @@
 
 from oslo_log import log as logging
 
-
 import nova.conf
 from nova.scheduler import filters
 from nova.scheduler.filters import utils
@@ -42,6 +41,18 @@ class AggregateImagePropertiesIsolation(filters.BaseHostFilter):
         cfg_separator = (CONF.filter_scheduler.
             aggregate_image_properties_isolation_separator)
 
+        if cfg_namespace:
+            LOG.warning(
+                "It is no longer possible to filter on arbitrary image "
+                "metadata properties, which includes standard properties "
+                "prefixed with '[filter_scheduler] "
+                "aggregate_image_properties_isolation_namespace'. "
+                "You should unset this option and consider using the isolated "
+                "aggregate filtering feature instead. "
+                "See '[scheduler] enable_isolated_aggregate_filtering' for "
+                "more information."
+            )
+
         image_props = spec_obj.image.properties if spec_obj.image else {}
         metadata = utils.aggregate_metadata_get_by_host(host_state)
 

releasenotes/notes/deprecated-AggregateImagePropertiesIsolation-conf-opts-ce601f7c08515586.yaml

@@ -0,0 +1,13 @@
+---
+deprecations:
+  - |
+    The ``[filter_scheduler] aggregate_image_properties_isolation_namespace``
+    and ``[filter_scheduler] aggregate_image_properties_isolation_separator``
+    config options have been deprecated for removal. These have been
+    effectively unusable since the 12.0.0 (Liberty) release, which removed the
+    ability for the ``AggregateImagePropertiesIsolation`` scheduler filter to
+    filter on any non-standard image metadata property. Users who require this
+    functionality should consider enforcing `aggregate isolation using
+    placement traits`__.
+
+    __ https://docs.openstack.org/nova/latest/reference/isolate-aggregates.html