84 lines
3.3 KiB
Python
84 lines
3.3 KiB
Python
# 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.
|
|
|
|
"""
|
|
Chance (Random) Scheduler implementation
|
|
"""
|
|
|
|
import random
|
|
|
|
from nova import exception
|
|
from nova.scheduler import driver
|
|
|
|
|
|
class ChanceScheduler(driver.Scheduler):
|
|
"""Implements Scheduler as a random node selector."""
|
|
|
|
def _filter_hosts(self, request_spec, hosts, **kwargs):
|
|
"""Filter a list of hosts based on request_spec."""
|
|
|
|
filter_properties = kwargs.get('filter_properties', {})
|
|
ignore_hosts = filter_properties.get('ignore_hosts', [])
|
|
hosts = [host for host in hosts if host not in ignore_hosts]
|
|
return hosts
|
|
|
|
def _schedule(self, context, topic, request_spec, **kwargs):
|
|
"""Picks a host that is up at random."""
|
|
|
|
elevated = context.elevated()
|
|
hosts = self.hosts_up(elevated, topic)
|
|
if not hosts:
|
|
msg = _("Is the appropriate service running?")
|
|
raise exception.NoValidHost(reason=msg)
|
|
|
|
hosts = self._filter_hosts(request_spec, hosts, **kwargs)
|
|
if not hosts:
|
|
msg = _("Could not find another compute")
|
|
raise exception.NoValidHost(reason=msg)
|
|
|
|
return hosts[int(random.random() * len(hosts))]
|
|
|
|
def schedule(self, context, topic, method, *_args, **kwargs):
|
|
"""Picks a host that is up at random."""
|
|
|
|
host = self._schedule(context, topic, None, **kwargs)
|
|
driver.cast_to_host(context, topic, host, method, **kwargs)
|
|
|
|
def schedule_run_instance(self, context, request_spec, *_args, **kwargs):
|
|
"""Create and run an instance or instances"""
|
|
num_instances = request_spec.get('num_instances', 1)
|
|
instances = []
|
|
for num in xrange(num_instances):
|
|
host = self._schedule(context, 'compute', request_spec, **kwargs)
|
|
request_spec['instance_properties']['launch_index'] = num
|
|
instance = self.create_instance_db_entry(context, request_spec)
|
|
driver.cast_to_compute_host(context, host,
|
|
'run_instance', instance_uuid=instance['uuid'], **kwargs)
|
|
instances.append(driver.encode_instance(instance))
|
|
# So if we loop around, create_instance_db_entry will actually
|
|
# create a new entry, instead of assume it's been created
|
|
# already
|
|
del request_spec['instance_properties']['uuid']
|
|
return instances
|
|
|
|
def schedule_prep_resize(self, context, request_spec, *args, **kwargs):
|
|
"""Select a target for resize."""
|
|
host = self._schedule(context, 'compute', request_spec, **kwargs)
|
|
driver.cast_to_compute_host(context, host, 'prep_resize', **kwargs)
|