nova/nova/tests/scheduler/test_least_cost_scheduler.py

147 lines
5.0 KiB
Python

# Copyright 2011 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 Least Cost Scheduler
"""
import copy
from nova import test
from nova.scheduler import least_cost
from nova.tests.scheduler import test_abstract_scheduler
MB = 1024 * 1024
class FakeHost(object):
def __init__(self, host_id, free_ram, io):
self.id = host_id
self.free_ram = free_ram
self.io = io
class WeightedSumTestCase(test.TestCase):
def test_empty_domain(self):
domain = []
weighted_fns = []
result = least_cost.weighted_sum(domain, weighted_fns)
expected = []
self.assertEqual(expected, result)
def test_basic_costing(self):
hosts = [
FakeHost(1, 512 * MB, 100),
FakeHost(2, 256 * MB, 400),
FakeHost(3, 512 * MB, 100),
]
weighted_fns = [
(1, lambda h: h.free_ram), # Fill-first, free_ram is a *cost*
(2, lambda h: h.io), # Avoid high I/O
]
costs = least_cost.weighted_sum(
domain=hosts, weighted_fns=weighted_fns)
# Each 256 MB unit of free-ram contributes 0.5 points by way of:
# cost = weight * (score/max_score) = 1 * (256/512) = 0.5
# Each 100 iops of IO adds 0.5 points by way of:
# cost = 2 * (100/400) = 2 * 0.25 = 0.5
expected = [1.5, 2.5, 1.5]
self.assertEqual(expected, costs)
class LeastCostSchedulerTestCase(test.TestCase):
def setUp(self):
super(LeastCostSchedulerTestCase, self).setUp()
class FakeZoneManager:
pass
zone_manager = FakeZoneManager()
states = test_abstract_scheduler.fake_zone_manager_service_states(
num_hosts=10)
zone_manager.service_states = states
self.sched = least_cost.LeastCostScheduler()
self.sched.zone_manager = zone_manager
def tearDown(self):
super(LeastCostSchedulerTestCase, self).tearDown()
def assertWeights(self, expected, num, request_spec, hosts):
weighted = self.sched.weigh_hosts("compute", request_spec, hosts)
self.assertDictListMatch(weighted, expected, approx_equal=True)
def test_no_hosts(self):
num = 1
request_spec = {}
hosts = []
expected = []
self.assertWeights(expected, num, request_spec, hosts)
def test_noop_cost_fn(self):
self.flags(least_cost_scheduler_cost_functions=[
'nova.scheduler.least_cost.noop_cost_fn'],
noop_cost_fn_weight=1)
num = 1
request_spec = {}
hosts = self.sched.filter_hosts(num, request_spec)
expected = [dict(weight=1, hostname=hostname)
for hostname, caps in hosts]
self.assertWeights(expected, num, request_spec, hosts)
def test_cost_fn_weights(self):
self.flags(least_cost_scheduler_cost_functions=[
'nova.scheduler.least_cost.noop_cost_fn'],
noop_cost_fn_weight=2)
num = 1
request_spec = {}
hosts = self.sched.filter_hosts(num, request_spec)
expected = [dict(weight=2, hostname=hostname)
for hostname, caps in hosts]
self.assertWeights(expected, num, request_spec, hosts)
def test_compute_fill_first_cost_fn(self):
self.flags(least_cost_scheduler_cost_functions=[
'nova.scheduler.least_cost.compute_fill_first_cost_fn'],
compute_fill_first_cost_fn_weight=1)
num = 1
instance_type = {'memory_mb': 1024}
request_spec = {'instance_type': instance_type}
svc_states = self.sched.zone_manager.service_states.iteritems()
all_hosts = [(host, services["compute"])
for host, services in svc_states
if "compute" in services]
hosts = self.sched.filter_hosts('compute', request_spec, all_hosts)
expected = []
for idx, (hostname, services) in enumerate(hosts):
caps = copy.deepcopy(services["compute"])
# Costs are normalized so over 10 hosts, each host with increasing
# free ram will cost 1/N more. Since the lowest cost host has some
# free ram, we add in the 1/N for the base_cost
weight = 0.1 + (0.1 * idx)
wtd_dict = dict(hostname=hostname, weight=weight,
capabilities=caps)
expected.append(wtd_dict)
self.assertWeights(expected, num, request_spec, hosts)