Files
gantt/nova/tests/scheduler/test_weights.py
Chris Behrens c728941c3d Refactor scheduling weights.
This makes scheduling weights more plugin friendly and creates shared
code that can be used by the host scheduler as well as the future cells
scheduler.  Weighing classes can now be specified much like you can
specify scheduling host filters.

The new weights code reverses the old behavior where lower weights win.
Higher weights are now the winners.

The least_cost module and configs have been deprecated, but are still
supported for backwards compatibility.  The code has moved to
nova.scheduler.weights.least_cost and been modified to work with the new
loadable-class code.  If any of the least_cost related config options are
specified, this least_cost weigher will be used.

For those not overriding the default least_cost config values, the new
RamWeigher class will be used.  The default behavior of the RamWeigher
class is the same default behavior as the old least_cost module.

The new weights code introduces a new config option
'scheduler_weight_classes' which is used to specify which weigher classes
to use.  The default is 'all classes', but modified if least_cost
deprecated config options are used, as mentioned above.

The RamWeigher class introduces a new config option
'ram_weight_multiplier'.  The default of 1.0 causes weights equal to the
free memory in MB to be returned, thus hosts with more free memory are
preferred (causes equal spreading).  Changing this value to a negative
number such as -1.0 will cause reverse behavior (fill first).

DocImpact

Change-Id: I1e5e5039c299db02f7287f2d33299ebf0b9732ce
2012-11-14 19:04:17 +00:00

118 lines
4.3 KiB
Python

# Copyright 2011-2012 OpenStack LLC.
# 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.
"""
Tests For Scheduler weights.
"""
from nova import context
from nova.scheduler import weights
from nova import test
from nova.tests import matchers
from nova.tests.scheduler import fakes
class TestWeighedHost(test.TestCase):
def test_dict_conversion(self):
host_state = fakes.FakeHostState('somehost', None, {})
host = weights.WeighedHost(host_state, 'someweight')
expected = {'weight': 'someweight',
'host': 'somehost'}
self.assertThat(host.to_dict(), matchers.DictMatches(expected))
def test_all_weighers(self):
classes = weights.all_weighers()
class_names = [cls.__name__ for cls in classes]
self.assertEqual(len(classes), 1)
self.assertIn('RAMWeigher', class_names)
def test_all_weighers_with_deprecated_config1(self):
self.flags(compute_fill_first_cost_fn_weight=-1.0)
classes = weights.all_weighers()
class_names = [cls.__name__ for cls in classes]
self.assertEqual(len(classes), 1)
self.assertIn('_LeastCostWeigher', class_names)
def test_all_weighers_with_deprecated_config2(self):
self.flags(least_cost_functions=['something'])
classes = weights.all_weighers()
class_names = [cls.__name__ for cls in classes]
self.assertEqual(len(classes), 1)
self.assertIn('_LeastCostWeigher', class_names)
class RamWeigherTestCase(test.TestCase):
def setUp(self):
super(RamWeigherTestCase, self).setUp()
self.host_manager = fakes.FakeHostManager()
self.weight_handler = weights.HostWeightHandler()
self.weight_classes = self.weight_handler.get_matching_classes(
['nova.scheduler.weights.ram.RAMWeigher'])
def _get_weighed_host(self, hosts, weight_properties=None):
if weight_properties is None:
weight_properties = {}
return self.weight_handler.get_weighed_objects(self.weight_classes,
hosts, weight_properties)[0]
def _get_all_hosts(self):
ctxt = context.get_admin_context()
fakes.mox_host_manager_db_calls(self.mox, ctxt)
self.mox.ReplayAll()
host_states = self.host_manager.get_all_host_states(ctxt)
self.mox.VerifyAll()
self.mox.ResetAll()
return host_states
def test_default_of_spreading_first(self):
hostinfo_list = self._get_all_hosts()
# host1: free_ram_mb=512
# host2: free_ram_mb=1024
# host3: free_ram_mb=3072
# host4: free_ram_mb=8192
# so, host4 should win:
weighed_host = self._get_weighed_host(hostinfo_list)
self.assertEqual(weighed_host.weight, 8192)
self.assertEqual(weighed_host.obj.host, 'host4')
def test_ram_filter_multiplier1(self):
self.flags(ram_weight_multiplier=-1.0)
hostinfo_list = self._get_all_hosts()
# host1: free_ram_mb=-512
# host2: free_ram_mb=-1024
# host3: free_ram_mb=-3072
# host4: free_ram_mb=-8192
# so, host1 should win:
weighed_host = self._get_weighed_host(hostinfo_list)
self.assertEqual(weighed_host.weight, -512)
self.assertEqual(weighed_host.obj.host, 'host1')
def test_ram_filter_multiplier2(self):
self.flags(ram_weight_multiplier=2.0)
hostinfo_list = self._get_all_hosts()
# host1: free_ram_mb=512 * 2
# host2: free_ram_mb=1024 * 2
# host3: free_ram_mb=3072 * 2
# host4: free_ram_mb=8192 * 2
# so, host4 should win:
weighed_host = self._get_weighed_host(hostinfo_list)
self.assertEqual(weighed_host.weight, 8192 * 2)
self.assertEqual(weighed_host.obj.host, 'host4')