RAM weigher for Nova - Mitaka

aggregate_ram.py

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#         http://www.apache.org/licenses/LICENSE-2.0
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from oslo_log import log as logging

import nova.conf
from nova.i18n import _LW
from nova.scheduler.filters import utils
from nova.scheduler import weights

CONF = nova.conf.CONF
LOG = logging.getLogger(__name__)


class AggregateRAMWeigher(weights.BaseHostWeigher):
    """AggregateRAMWeigher with per-aggregate RAM weight multiplier.

    Fallback to global ram_weight_multiplier if no per-aggregate setting found.
    """

    def _weigh_object(self, host_state, weight_properties):

        aggregate_vals = utils.aggregate_values_from_key(
            host_state,
            'ram_weight_multiplier')

        try:
            weight = utils.validate_num_values(
                aggregate_vals,
                CONF.ram_weight_multiplier, cast_to=float)
        except ValueError as e:
            LOG.warning(_LW("Could not decode ram_weight_multiplier: '%s'"), e)
            weight = CONF.ram_weight_multiplier

        return host_state.free_ram_mb * weight