Merge "Add scheduler filter: TypeAffinityFilter"

4 files changed, 80 insertions, 3 deletions

diff --git a/nova/db/api.py b/nova/db/api.py
index f2f74cc55..ff72aff37 100644
--- a/nova/db/api.py
+++ b/nova/db/api.py
@@ -571,15 +571,20 @@ def instance_get_active_by_window_joined(context, begin, end=None,
 
 
 def instance_get_all_by_project(context, project_id):
-    """Get all instance belonging to a project."""
+    """Get all instances belonging to a project."""
     return IMPL.instance_get_all_by_project(context, project_id)
 
 
 def instance_get_all_by_host(context, host):
-    """Get all instance belonging to a host."""
+    """Get all instances belonging to a host."""
     return IMPL.instance_get_all_by_host(context, host)
 
 
+def instance_get_all_by_host_and_not_type(context, host, type_id=None):
+    """Get all instances belonging to a host with a different type_id."""
+    return IMPL.instance_get_all_by_host_and_not_type(context, host, type_id)
+
+
 def instance_get_all_by_reservation(context, reservation_id):
     """Get all instances belonging to a reservation."""
     return IMPL.instance_get_all_by_reservation(context, reservation_id)
diff --git a/nova/db/sqlalchemy/api.py b/nova/db/sqlalchemy/api.py
index 56a25ad71..88ddeac34 100644
--- a/nova/db/sqlalchemy/api.py
+++ b/nova/db/sqlalchemy/api.py
@@ -1548,6 +1548,12 @@ def instance_get_all_by_host(context, host):
     return _instance_get_all_query(context).filter_by(host=host).all()
 
 
+@require_admin_context
+def instance_get_all_by_host_and_not_type(context, host, type_id=None):
+    return _instance_get_all_query(context).filter_by(host=host).\
+                   filter(models.Instance.instance_type_id != type_id).all()
+
+
 @require_context
 def instance_get_all_by_project(context, project_id):
     authorize_project_context(context, project_id)
diff --git a/nova/scheduler/filters/type_filter.py b/nova/scheduler/filters/type_filter.py
new file mode 100644
index 000000000..a8d842d52
--- /dev/null
+++ b/nova/scheduler/filters/type_filter.py
@@ -0,0 +1,39 @@
+# Copyright (c) 2012 The Cloudscaling Group, Inc.
+#
+# All Rights Reserved.
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from nova import db
+from nova.scheduler import filters
+
+
+class TypeAffinityFilter(filters.BaseHostFilter):
+    """TypeAffinityFilter doesn't allow more then one VM type per host.
+
+    Note: this works best with compute_fill_first_cost_fn_weight
+    (dispersion) set to 1 (-1 by default).
+    """
+
+    def host_passes(self, host_state, filter_properties):
+        """Dynamically limits hosts to one instance type
+
+        Return False if host has any instance types other then the requested
+        type. Return True if all instance types match or if host is empty.
+        """
+
+        instance_type = filter_properties.get('instance_type')
+        context = filter_properties['context'].elevated()
+        instances_other_type = db.instance_get_all_by_host_and_not_type(
+                     context, host_state.host, instance_type['id'])
+        return len(instances_other_type) == 0
diff --git a/nova/tests/scheduler/test_host_filters.py b/nova/tests/scheduler/test_host_filters.py
index 5659d9467..22a162aa2 100644
--- a/nova/tests/scheduler/test_host_filters.py
+++ b/nova/tests/scheduler/test_host_filters.py
@@ -45,7 +45,7 @@ class HostFiltersTestCase(test.TestCase):
                 ['and', ['>=', '$free_ram_mb', 1024],
                         ['>=', '$free_disk_mb', 200 * 1024]])
         # This has a side effect of testing 'get_filter_classes'
-        # when specifing a method (in this case, our standard filters)
+        # when specifying a method (in this case, our standard filters)
         classes = filters.get_filter_classes(
                 ['nova.scheduler.filters.standard_filters'])
         self.class_map = {}
@@ -174,6 +174,33 @@ class HostFiltersTestCase(test.TestCase):
                  'service': service})
         self.assertTrue(filt_cls.host_passes(host, filter_properties))
 
+    def test_type_filter(self):
+        self._stub_service_is_up(True)
+        filt_cls = self.class_map['TypeAffinityFilter']()
+
+        filter_properties = {'context': self.context,
+                             'instance_type': {'id': 1}}
+        filter2_properties = {'context': self.context,
+                             'instance_type': {'id': 2}}
+
+        capabilities = {'enabled': True}
+        service = {'disabled': False}
+        host = fakes.FakeHostState('fake_host', 'compute',
+                {'capabilities': capabilities,
+                 'service': service})
+        #True since empty
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+        fakes.FakeInstance(context=self.context,
+                           params={'host': 'fake_host', 'instance_type_id': 1})
+        #True since same type
+        self.assertTrue(filt_cls.host_passes(host, filter_properties))
+        #False since different type
+        self.assertFalse(filt_cls.host_passes(host, filter2_properties))
+        #False since node not homogeneous
+        fakes.FakeInstance(context=self.context,
+                           params={'host': 'fake_host', 'instance_type_id': 2})
+        self.assertFalse(filt_cls.host_passes(host, filter_properties))
+
     def test_ram_filter_fails_on_memory(self):
         self._stub_service_is_up(True)
         filt_cls = self.class_map['RamFilter']()