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# 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.config import cfg
from nova import db
from nova.openstack.common import log as logging
from nova.scheduler import filters
LOG = logging.getLogger(__name__)
ram_allocation_ratio_opt = cfg.FloatOpt('ram_allocation_ratio',
default=1.5,
help='Virtual ram to physical ram allocation ratio which affects '
'all ram filters. This configuration specifies a global ratio '
'for RamFilter. For AggregateRamFilter, it will fall back to '
'this configuration value if no per-aggregate setting found.')
CONF = cfg.CONF
CONF.register_opt(ram_allocation_ratio_opt)
class BaseRamFilter(filters.BaseHostFilter):
def _get_ram_allocation_ratio(self, host_state, filter_properties):
raise NotImplementedError
def host_passes(self, host_state, filter_properties):
"""Only return hosts with sufficient available RAM."""
instance_type = filter_properties.get('instance_type')
requested_ram = instance_type['memory_mb']
free_ram_mb = host_state.free_ram_mb
total_usable_ram_mb = host_state.total_usable_ram_mb
ram_allocation_ratio = self._get_ram_allocation_ratio(host_state,
filter_properties)
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, filter_properties):
return CONF.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, filter_properties):
context = filter_properties['context'].elevated()
# TODO(uni): DB query in filter is a performance hit, especially for
# system with lots of hosts. Will need a general solution here to fix
# all filters with aggregate DB call things.
metadata = db.aggregate_metadata_get_by_host(
context, host_state.host, key='ram_allocation_ratio')
aggregate_vals = metadata.get('ram_allocation_ratio', set())
num_values = len(aggregate_vals)
if num_values == 0:
return CONF.ram_allocation_ratio
if num_values > 1:
LOG.warning(_("%(num_values)d ratio values found, "
"of which the minimum value will be used."),
{'num_values': num_values})
try:
ratio = float(min(aggregate_vals))
except ValueError as e:
LOG.warning(_("Could not decode ram_allocation_ratio: "
"'%(e)s'") % locals())
ratio = CONF.ram_allocation_ratio
return ratio
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