diff options
Diffstat (limited to 'nova/compute/manager.py')
| -rw-r--r-- | nova/compute/manager.py | 110 |
1 files changed, 94 insertions, 16 deletions
diff --git a/nova/compute/manager.py b/nova/compute/manager.py index e5f6ace00f..dbf8308515 100644 --- a/nova/compute/manager.py +++ b/nova/compute/manager.py @@ -1587,7 +1587,11 @@ class ComputeManager(manager.Manager): return [_decode(f) for f in injected_files] def _validate_instance_group_policy(self, context, instance, - scheduler_hints): + scheduler_hints=None): + + if CONF.workarounds.disable_group_policy_check_upcall: + return + # NOTE(russellb) Instance group policy is enforced by the scheduler. # However, there is a race condition with the enforcement of # the policy. Since more than one instance may be scheduled at the @@ -1596,29 +1600,63 @@ class ComputeManager(manager.Manager): # multiple instances with an affinity policy could end up on different # hosts. This is a validation step to make sure that starting the # instance here doesn't violate the policy. - group_hint = scheduler_hints.get('group') - if not group_hint: - return - - # The RequestSpec stores scheduler_hints as key=list pairs so we need - # to check the type on the value and pull the single entry out. The - # API request schema validates that the 'group' hint is a single value. - if isinstance(group_hint, list): - group_hint = group_hint[0] + if scheduler_hints is not None: + # only go through here if scheduler_hints is provided, even if it + # is empty. + group_hint = scheduler_hints.get('group') + if not group_hint: + return + else: + # The RequestSpec stores scheduler_hints as key=list pairs so + # we need to check the type on the value and pull the single + # entry out. The API request schema validates that + # the 'group' hint is a single value. + if isinstance(group_hint, list): + group_hint = group_hint[0] + + group = objects.InstanceGroup.get_by_hint(context, group_hint) + else: + # TODO(ganso): a call to DB can be saved by adding request_spec + # to rpcapi payload of live_migration, pre_live_migration and + # check_can_live_migrate_destination + try: + group = objects.InstanceGroup.get_by_instance_uuid( + context, instance.uuid) + except exception.InstanceGroupNotFound: + return - @utils.synchronized(group_hint) - def _do_validation(context, instance, group_hint): - group = objects.InstanceGroup.get_by_hint(context, group_hint) + @utils.synchronized(group['uuid']) + def _do_validation(context, instance, group): if group.policy and 'anti-affinity' == group.policy: + + # instances on host instances_uuids = objects.InstanceList.get_uuids_by_host( context, self.host) ins_on_host = set(instances_uuids) + + # instance param is just for logging, the nodename obtained is + # not actually related to the instance at all + nodename = self._get_nodename(instance) + + # instances being migrated to host + migrations = ( + objects.MigrationList.get_in_progress_by_host_and_node( + context, self.host, nodename)) + migration_vm_uuids = set([mig['instance_uuid'] + for mig in migrations]) + + total_instances = migration_vm_uuids | ins_on_host + + # refresh group to get updated members within locked block + group = objects.InstanceGroup.get_by_uuid(context, + group['uuid']) members = set(group.members) # Determine the set of instance group members on this host # which are not the instance in question. This is used to # determine how many other members from the same anti-affinity # group can be on this host. - members_on_host = ins_on_host & members - set([instance.uuid]) + members_on_host = (total_instances & members - + set([instance.uuid])) rules = group.rules if rules and 'max_server_per_host' in rules: max_server = rules['max_server_per_host'] @@ -1630,6 +1668,12 @@ class ComputeManager(manager.Manager): raise exception.RescheduledException( instance_uuid=instance.uuid, reason=msg) + + # NOTE(ganso): The check for affinity below does not work and it + # can easily be violated because the lock happens in different + # compute hosts. + # The only fix seems to be a DB lock to perform the check whenever + # setting the host field to an instance. elif group.policy and 'affinity' == group.policy: group_hosts = group.get_hosts(exclude=[instance.uuid]) if group_hosts and self.host not in group_hosts: @@ -1638,8 +1682,7 @@ class ComputeManager(manager.Manager): instance_uuid=instance.uuid, reason=msg) - if not CONF.workarounds.disable_group_policy_check_upcall: - _do_validation(context, instance, group_hint) + _do_validation(context, instance, group) def _log_original_error(self, exc_info, instance_uuid): LOG.error('Error: %s', exc_info[1], instance_uuid=instance_uuid, @@ -4773,10 +4816,24 @@ class ComputeManager(manager.Manager): with self._error_out_instance_on_exception( context, instance, instance_state=instance_state),\ errors_out_migration_ctxt(migration): + self._send_prep_resize_notifications( context, instance, fields.NotificationPhase.START, instance_type) try: + scheduler_hints = self._get_scheduler_hints(filter_properties, + request_spec) + # Error out if this host cannot accept the new instance due + # to anti-affinity. At this point the migration is already + # in-progress, so this is the definitive moment to abort due to + # the policy violation. Also, exploding here is covered by the + # cleanup methods in except block. + try: + self._validate_instance_group_policy(context, instance, + scheduler_hints) + except exception.RescheduledException as e: + raise exception.InstanceFaultRollback(inner_exception=e) + self._prep_resize(context, image, instance, instance_type, filter_properties, node, migration, request_spec, @@ -6811,6 +6868,20 @@ class ComputeManager(manager.Manager): :param limits: objects.SchedulerLimits object for this live migration. :returns: a LiveMigrateData object (hypervisor-dependent) """ + + # Error out if this host cannot accept the new instance due + # to anti-affinity. This check at this moment is not very accurate, as + # multiple requests may be happening concurrently and miss the lock, + # but when it works it provides a better user experience by failing + # earlier. Also, it should be safe to explode here, error becomes + # NoValidHost and instance status remains ACTIVE. + try: + self._validate_instance_group_policy(ctxt, instance) + except exception.RescheduledException as e: + msg = ("Failed to validate instance group policy " + "due to: {}".format(e)) + raise exception.MigrationPreCheckError(reason=msg) + src_compute_info = obj_base.obj_to_primitive( self._get_compute_info(ctxt, instance.host)) dst_compute_info = obj_base.obj_to_primitive( @@ -6949,6 +7020,13 @@ class ComputeManager(manager.Manager): """ LOG.debug('pre_live_migration data is %s', migrate_data) + # Error out if this host cannot accept the new instance due + # to anti-affinity. At this point the migration is already in-progress, + # so this is the definitive moment to abort due to the policy + # violation. Also, it should be safe to explode here. The instance + # status remains ACTIVE, migration status failed. + self._validate_instance_group_policy(context, instance) + migrate_data.old_vol_attachment_ids = {} bdms = objects.BlockDeviceMappingList.get_by_instance_uuid( context, instance.uuid) |