diff --git a/nova/scheduler/zone.py b/nova/scheduler/zone.py new file mode 100644 index 00000000..ec2166ad --- /dev/null +++ b/nova/scheduler/zone.py @@ -0,0 +1,58 @@ +# vim: tabstop=4 shiftwidth=4 softtabstop=4 + +# Copyright (c) 2010 Openstack, LLC. +# Copyright 2010 United States Government as represented by the +# Administrator of the National Aeronautics and Space Administration. +# 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. + +""" +Availability Zone Scheduler implementation +""" + +import random + +from nova.scheduler import driver +from nova import db + + +class ZoneScheduler(driver.Scheduler): + """Implements Scheduler as a random node selector.""" + + def hosts_up_with_zone(self, context, topic, zone): + """Return the list of hosts that have a running service + for topic and availability zone (if defined). + """ + + if zone is None: + return self.hosts_up(context, topic) + + services = db.service_get_all_by_topic(context, topic) + return [service.host + for service in services + if self.service_is_up(service) + and service.availability_zone == zone] + + + def schedule(self, context, topic, *_args, **_kwargs): + """Picks a host that is up at random in selected + availability zone (if defined). + """ + + zone = _kwargs.get('availability_zone') + hosts = self.hosts_up_with_zone(context, topic, zone) + if not hosts: + raise driver.NoValidHost(_("No hosts found")) + return hosts[int(random.random() * len(hosts))] +