Coverage for nova/scheduler/weights/cpu.py: 100%

1# Copyright (c) 2016, Red Hat Inc. 

2# All Rights Reserved. 

3# 

4# Licensed under the Apache License, Version 2.0 (the "License"); you may 

5# not use this file except in compliance with the License. You may obtain 

6# a copy of the License at 

7# 

8# http://www.apache.org/licenses/LICENSE-2.0 

9# 

10# Unless required by applicable law or agreed to in writing, software 

11# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 

12# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 

13# License for the specific language governing permissions and limitations 

14# under the License. 

15 

16""" 

17CPU Weigher. Weigh hosts by their CPU usage. 

18 

19The default is to spread instances across all hosts evenly. If you prefer 

20stacking, you can set the 'cpu_weight_multiplier' option (by configuration 

21or aggregate metadata) to a negative number and the weighing has the opposite 

22effect of the default. 

23""" 

24 

25import nova.conf 

26from nova.scheduler import utils 

27from nova.scheduler import weights 

28 

29CONF = nova.conf.CONF 

30 

31 

32class CPUWeigher(weights.BaseHostWeigher): 

33 minval = 0 

34 

35 def weight_multiplier(self, host_state): 

36 """Override the weight multiplier.""" 

37 return utils.get_weight_multiplier( 

38 host_state, 'cpu_weight_multiplier', 

39 CONF.filter_scheduler.cpu_weight_multiplier) 

40 

41 def _weigh_object(self, host_state, weight_properties): 

42 """Higher weights win. We want spreading to be the default.""" 

43 vcpus_free = ( 

44 host_state.vcpus_total * host_state.cpu_allocation_ratio - 

45 host_state.vcpus_used) 

46 return vcpus_free