144 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			144 lines
		
	
	
		
			4.7 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
# Copyright (c) 2012 OpenStack Foundation
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# All Rights Reserved.
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#
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#    Licensed under the Apache License, Version 2.0 (the "License"); you may
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#    not use this file except in compliance with the License. You may obtain
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#    a copy of the License at
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#
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#         http://www.apache.org/licenses/LICENSE-2.0
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#
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#    Unless required by applicable law or agreed to in writing, software
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#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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#    License for the specific language governing permissions and limitations
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#    under the License.
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"""Availability zone helper functions."""
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from oslo.config import cfg
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from nova import db
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from nova.openstack.common import memorycache
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# NOTE(vish): azs don't change that often, so cache them for an hour to
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#             avoid hitting the db multiple times on every request.
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AZ_CACHE_SECONDS = 60 * 60
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MC = None
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availability_zone_opts = [
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    cfg.StrOpt('internal_service_availability_zone',
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               default='internal',
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               help='availability_zone to show internal services under'),
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    cfg.StrOpt('default_availability_zone',
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               default='nova',
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               help='default compute node availability_zone'),
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    ]
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CONF = cfg.CONF
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CONF.register_opts(availability_zone_opts)
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def _get_cache():
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    global MC
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    if MC is None:
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        MC = memorycache.get_client()
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    return MC
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def reset_cache():
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    """Reset the cache, mainly for testing purposes and update
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    availability_zone for host aggregate
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    """
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    global MC
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    MC = None
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def _make_cache_key(host):
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    return "azcache-%s" % host.encode('utf-8')
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def set_availability_zones(context, services):
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    # Makes sure services isn't a sqlalchemy object
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    services = [dict(service.iteritems()) for service in services]
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    metadata = db.aggregate_host_get_by_metadata_key(context,
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            key='availability_zone')
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    for service in services:
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        az = CONF.internal_service_availability_zone
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        if service['topic'] == "compute":
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            if metadata.get(service['host']):
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                az = u','.join(list(metadata[service['host']]))
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            else:
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                az = CONF.default_availability_zone
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                # update the cache
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                cache = _get_cache()
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                cache_key = _make_cache_key(service['host'])
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                cache.delete(cache_key)
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                cache.set(cache_key, az, AZ_CACHE_SECONDS)
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        service['availability_zone'] = az
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    return services
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def get_host_availability_zone(context, host, conductor_api=None):
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    if conductor_api:
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        metadata = conductor_api.aggregate_metadata_get_by_host(
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            context, host, key='availability_zone')
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    else:
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        metadata = db.aggregate_metadata_get_by_host(
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            context, host, key='availability_zone')
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    if 'availability_zone' in metadata:
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        az = list(metadata['availability_zone'])[0]
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    else:
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        az = CONF.default_availability_zone
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    return az
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def get_availability_zones(context, get_only_available=False):
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    """Return available and unavailable zones on demands.
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       :param get_only_available: flag to determine whether to return
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           available zones only, default False indicates return both
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           available zones and not available zones, True indicates return
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           available zones only
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    """
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    enabled_services = db.service_get_all(context, False)
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    enabled_services = set_availability_zones(context, enabled_services)
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    available_zones = []
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    for zone in [service['availability_zone'] for service
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                 in enabled_services]:
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        if zone not in available_zones:
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            available_zones.append(zone)
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    if not get_only_available:
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        disabled_services = db.service_get_all(context, True)
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        disabled_services = set_availability_zones(context, disabled_services)
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        not_available_zones = []
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        zones = [service['availability_zone'] for service in disabled_services
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                if service['availability_zone'] not in available_zones]
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        for zone in zones:
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            if zone not in not_available_zones:
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                not_available_zones.append(zone)
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        return (available_zones, not_available_zones)
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    else:
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        return available_zones
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def get_instance_availability_zone(context, instance):
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    """Return availability zone of specified instance."""
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    host = str(instance.get('host'))
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    if not host:
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        return None
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    cache_key = _make_cache_key(host)
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    cache = _get_cache()
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    az = cache.get(cache_key)
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    if not az:
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        elevated = context.elevated()
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        az = get_host_availability_zone(elevated, host)
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        cache.set(cache_key, az, AZ_CACHE_SECONDS)
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    return az
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