nova/nova/scheduler/filters/ram_filter.py

94 lines
3.5 KiB
Python

# Copyright (c) 2011 OpenStack Foundation
# Copyright (c) 2012 Cloudscaling
# 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 oslo_log import log as logging
from nova.scheduler import filters
from nova.scheduler.filters import utils
LOG = logging.getLogger(__name__)
class BaseRamFilter(filters.BaseHostFilter):
RUN_ON_REBUILD = False
def _get_ram_allocation_ratio(self, host_state, spec_obj):
raise NotImplementedError
def host_passes(self, host_state, spec_obj):
"""Only return hosts with sufficient available RAM."""
requested_ram = spec_obj.memory_mb
free_ram_mb = host_state.free_ram_mb
total_usable_ram_mb = host_state.total_usable_ram_mb
# Do not allow an instance to overcommit against itself, only against
# other instances.
if not total_usable_ram_mb >= requested_ram:
LOG.debug("%(host_state)s does not have %(requested_ram)s MB "
"usable ram before overcommit, it only has "
"%(usable_ram)s MB.",
{'host_state': host_state,
'requested_ram': requested_ram,
'usable_ram': total_usable_ram_mb})
return False
ram_allocation_ratio = self._get_ram_allocation_ratio(host_state,
spec_obj)
memory_mb_limit = total_usable_ram_mb * ram_allocation_ratio
used_ram_mb = total_usable_ram_mb - free_ram_mb
usable_ram = memory_mb_limit - used_ram_mb
if not usable_ram >= requested_ram:
LOG.debug("%(host_state)s does not have %(requested_ram)s MB "
"usable ram, it only has %(usable_ram)s MB usable ram.",
{'host_state': host_state,
'requested_ram': requested_ram,
'usable_ram': usable_ram})
return False
# save oversubscription limit for compute node to test against:
host_state.limits['memory_mb'] = memory_mb_limit
return True
class RamFilter(BaseRamFilter):
"""Ram Filter with over subscription flag."""
def _get_ram_allocation_ratio(self, host_state, spec_obj):
return host_state.ram_allocation_ratio
class AggregateRamFilter(BaseRamFilter):
"""AggregateRamFilter with per-aggregate ram subscription flag.
Fall back to global ram_allocation_ratio if no per-aggregate setting found.
"""
def _get_ram_allocation_ratio(self, host_state, spec_obj):
aggregate_vals = utils.aggregate_values_from_key(
host_state,
'ram_allocation_ratio')
try:
ratio = utils.validate_num_values(
aggregate_vals, host_state.ram_allocation_ratio, cast_to=float)
except ValueError as e:
LOG.warning("Could not decode ram_allocation_ratio: '%s'", e)
ratio = host_state.ram_allocation_ratio
return ratio