300 lines
11 KiB
Python
300 lines
11 KiB
Python
# vim: tabstop=4 shiftwidth=4 softtabstop=4
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# Copyright (c) 2010 Openstack, LLC.
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# Copyright 2010 United States Government as represented by the
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# Administrator of the National Aeronautics and Space Administration.
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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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"""
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Scheduler base class that all Schedulers should inherit from
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"""
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import datetime
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from nova import db
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from nova import exception
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from nova import flags
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from nova import log as logging
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from nova import rpc
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from nova import utils
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from nova.compute import power_state
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FLAGS = flags.FLAGS
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flags.DEFINE_integer('service_down_time', 60,
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'maximum time since last checkin for up service')
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flags.DECLARE('instances_path', 'nova.compute.manager')
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class NoValidHost(exception.Error):
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"""There is no valid host for the command."""
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pass
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class WillNotSchedule(exception.Error):
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"""The specified host is not up or doesn't exist."""
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pass
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class Scheduler(object):
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"""The base class that all Scheduler clases should inherit from."""
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def __init__(self):
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self.zone_manager = None
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def set_zone_manager(self, zone_manager):
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"""Called by the Scheduler Service to supply a ZoneManager."""
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self.zone_manager = zone_manager
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@staticmethod
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def service_is_up(service):
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"""Check whether a service is up based on last heartbeat."""
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last_heartbeat = service['updated_at'] or service['created_at']
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# Timestamps in DB are UTC.
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elapsed = utils.utcnow() - last_heartbeat
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return elapsed < datetime.timedelta(seconds=FLAGS.service_down_time)
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def hosts_up(self, context, topic):
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"""Return the list of hosts that have a running service for topic."""
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services = db.service_get_all_by_topic(context, topic)
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return [service.host
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for service in services
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if self.service_is_up(service)]
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def schedule(self, context, topic, *_args, **_kwargs):
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"""Must override at least this method for scheduler to work."""
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raise NotImplementedError(_("Must implement a fallback schedule"))
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def schedule_live_migration(self, context, instance_id, dest):
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"""Live migration scheduling method.
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:param context:
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:param instance_id:
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:param dest: destination host
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:return:
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The host where instance is running currently.
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Then scheduler send request that host.
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"""
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# Whether instance exists and is running.
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instance_ref = db.instance_get(context, instance_id)
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# Checking instance.
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self._live_migration_src_check(context, instance_ref)
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# Checking destination host.
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self._live_migration_dest_check(context, instance_ref, dest)
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# Common checking.
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self._live_migration_common_check(context, instance_ref, dest)
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# Changing instance_state.
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db.instance_set_state(context,
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instance_id,
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power_state.PAUSED,
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'migrating')
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# Changing volume state
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for volume_ref in instance_ref['volumes']:
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db.volume_update(context,
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volume_ref['id'],
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{'status': 'migrating'})
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# Return value is necessary to send request to src
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# Check _schedule() in detail.
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src = instance_ref['host']
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return src
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def _live_migration_src_check(self, context, instance_ref):
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"""Live migration check routine (for src host).
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:param context: security context
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:param instance_ref: nova.db.sqlalchemy.models.Instance object
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"""
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# Checking instance is running.
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if (power_state.RUNNING != instance_ref['state'] or \
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'running' != instance_ref['state_description']):
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raise exception.InstanceNotRunning(instance_id=instance_ref['id'])
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# Checing volume node is running when any volumes are mounted
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# to the instance.
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if len(instance_ref['volumes']) != 0:
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services = db.service_get_all_by_topic(context, 'volume')
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if len(services) < 1 or not self.service_is_up(services[0]):
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raise exception.VolumeServiceUnavailable()
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# Checking src host exists and compute node
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src = instance_ref['host']
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services = db.service_get_all_compute_by_host(context, src)
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# Checking src host is alive.
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if not self.service_is_up(services[0]):
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raise exception.ComputeServiceUnavailable(host=src)
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def _live_migration_dest_check(self, context, instance_ref, dest):
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"""Live migration check routine (for destination host).
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:param context: security context
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:param instance_ref: nova.db.sqlalchemy.models.Instance object
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:param dest: destination host
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"""
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# Checking dest exists and compute node.
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dservice_refs = db.service_get_all_compute_by_host(context, dest)
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dservice_ref = dservice_refs[0]
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# Checking dest host is alive.
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if not self.service_is_up(dservice_ref):
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raise exception.ComputeServiceUnavailable(host=dest)
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# Checking whether The host where instance is running
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# and dest is not same.
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src = instance_ref['host']
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if dest == src:
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raise exception.UnableToMigrateToSelf(
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instance_id=instance_ref['id'],
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host=dest)
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# Checking dst host still has enough capacities.
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self.assert_compute_node_has_enough_resources(context,
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instance_ref,
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dest)
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def _live_migration_common_check(self, context, instance_ref, dest):
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"""Live migration common check routine.
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Below checkings are followed by
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http://wiki.libvirt.org/page/TodoPreMigrationChecks
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:param context: security context
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:param instance_ref: nova.db.sqlalchemy.models.Instance object
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:param dest: destination host
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"""
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# Checking shared storage connectivity
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self.mounted_on_same_shared_storage(context, instance_ref, dest)
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# Checking dest exists.
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dservice_refs = db.service_get_all_compute_by_host(context, dest)
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dservice_ref = dservice_refs[0]['compute_node'][0]
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# Checking original host( where instance was launched at) exists.
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try:
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oservice_refs = db.service_get_all_compute_by_host(context,
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instance_ref['launched_on'])
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except exception.NotFound:
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raise exception.SourceHostUnavailable()
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oservice_ref = oservice_refs[0]['compute_node'][0]
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# Checking hypervisor is same.
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orig_hypervisor = oservice_ref['hypervisor_type']
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dest_hypervisor = dservice_ref['hypervisor_type']
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if orig_hypervisor != dest_hypervisor:
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raise exception.InvalidHypervisorType()
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# Checkng hypervisor version.
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orig_hypervisor = oservice_ref['hypervisor_version']
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dest_hypervisor = dservice_ref['hypervisor_version']
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if orig_hypervisor > dest_hypervisor:
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raise exception.DestinationHypervisorTooOld()
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# Checking cpuinfo.
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try:
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rpc.call(context,
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db.queue_get_for(context, FLAGS.compute_topic, dest),
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{"method": 'compare_cpu',
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"args": {'cpu_info': oservice_ref['cpu_info']}})
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except rpc.RemoteError:
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src = instance_ref['host']
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logging.exception(_("host %(dest)s is not compatible with "
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"original host %(src)s.") % locals())
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raise
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def assert_compute_node_has_enough_resources(self, context,
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instance_ref, dest):
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"""Checks if destination host has enough resource for live migration.
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Currently, only memory checking has been done.
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If storage migration(block migration, meaning live-migration
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without any shared storage) will be available, local storage
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checking is also necessary.
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:param context: security context
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:param instance_ref: nova.db.sqlalchemy.models.Instance object
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:param dest: destination host
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"""
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# Getting instance information
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hostname = instance_ref['hostname']
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# Getting host information
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service_refs = db.service_get_all_compute_by_host(context, dest)
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compute_node_ref = service_refs[0]['compute_node'][0]
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mem_total = int(compute_node_ref['memory_mb'])
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mem_used = int(compute_node_ref['memory_mb_used'])
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mem_avail = mem_total - mem_used
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mem_inst = instance_ref['memory_mb']
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if mem_avail <= mem_inst:
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reason = _("Unable to migrate %(hostname)s to destination: "
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"%(dest)s (host:%(mem_avail)s <= instance:"
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"%(mem_inst)s)")
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raise exception.MigrationError(reason=reason % locals())
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def mounted_on_same_shared_storage(self, context, instance_ref, dest):
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"""Check if the src and dest host mount same shared storage.
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At first, dest host creates temp file, and src host can see
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it if they mounts same shared storage. Then src host erase it.
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:param context: security context
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:param instance_ref: nova.db.sqlalchemy.models.Instance object
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:param dest: destination host
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"""
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src = instance_ref['host']
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dst_t = db.queue_get_for(context, FLAGS.compute_topic, dest)
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src_t = db.queue_get_for(context, FLAGS.compute_topic, src)
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try:
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# create tmpfile at dest host
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filename = rpc.call(context, dst_t,
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{"method": 'create_shared_storage_test_file'})
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# make sure existence at src host.
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rpc.call(context, src_t,
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{"method": 'check_shared_storage_test_file',
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"args": {'filename': filename}})
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except rpc.RemoteError:
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ipath = FLAGS.instances_path
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logging.error(_("Cannot confirm tmpfile at %(ipath)s is on "
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"same shared storage between %(src)s "
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"and %(dest)s.") % locals())
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raise
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finally:
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rpc.call(context, dst_t,
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{"method": 'cleanup_shared_storage_test_file',
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"args": {'filename': filename}})
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