Favor reserved host - Nova scheduler - Mitaka

reserved_host_for_tenant_weigher.py

from oslo_config import cfg

from nova.scheduler import weights

CONF = cfg.CONF

opts = [
    cfg.FloatOpt('reserved_host_for_tenant_weight_multiplier',
                 default=1.0,
                 help='Multiplier used for reserved host.  Negative '
                      'numbers mean to stack vs spread.'),
]

CONF.register_opts(opts)


class ReservedHostForTenantWeigher(weights.BaseHostWeigher):
    def weight_multiplier(self):
        return CONF.reserved_host_for_tenant_weight_multiplier

    def _weigh_object(self, host_state, weight_properties):
        stats = host_state.stats

        if stats.get('reserved_for_tenant_id'):
            return 1.0

        return 0.0

tenant_filter.py

from nova.scheduler import filters


def normalize_uuid(uuid):
    return uuid.lower().replace('-', '')


class TenantFilter(filters.BaseHostFilter):

    def host_passes(self, host_state, spec_obj):
        project_id = normalize_uuid(spec_obj.project_id)
        stats = host_state.stats

        reserved_for = stats.get('reserved_for_tenant_id')
        return not reserved_for or (
            normalize_uuid(reserved_for) == project_id
        )