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<p class="MsoNormal">Hi all,<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">In kilo (yeah I know it’s an old release, but still :)), I was getting a nova errors for DetachedInstanceError on instance.get_by_uuid().<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 ERROR nova.api.metadata.handler [req-5aa7b422-d6c0-424e-b40f-cea79d3a3963 - - - - -] Failed to get metadata for instance id: 859aba9c-7620-4cbf-a5aa-f6f29c320980<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler Traceback (most recent call last):<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/api/metadata/handler.py", line 220, in _handle_instance_id_request<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler remote_address)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/api/metadata/handler.py", line 106, in get_metadata_by_instance_id<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler instance_id, address)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/api/metadata/base.py", line 531, in get_metadata_by_instance_id<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler instance = objects.Instance.get_by_uuid(ctxt, instance_id)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/objects/base.py", line 163, in wrapper<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler result = fn(cls, context, *args, **kwargs)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/objects/instance.py", line 654, in get_by_uuid<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler expected_attrs)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/objects/instance.py", line 608, in _from_db_object<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler instance._maybe_migrate_flavor(db_inst, expected_attrs)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/nova/objects/instance.py", line 535, in _maybe_migrate_flavor<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler if instance_extra.get('flavor') is not None:<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/oslo_db/sqlalchemy/models.py", line 60, in get<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler return getattr(self, key, default)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 239, in __get__<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler return self.impl.get(instance_state(instance), dict_)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/attributes.py", line 591, in get<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler value = self.callable_(state, passive)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler File "/usr/lib64/python2.7/site-packages/sqlalchemy/orm/strategies.py", line 279, in _load_for_state<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler (orm_util.state_str(state), self.key)<o:p></o:p></p>
<p class="MsoNormal">2016-10-05 18:30:53.791 103618 TRACE nova.api.metadata.handler DetachedInstanceError: Parent instance <InstanceExtra at 0x6f43390> is not bound to a Session; deferred load operation of attribute 'flavor' cannot proceed<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Now I've fixed it by adding a "joinedload" in the database query (in instance_get_by_uuid()) on 'extra'.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">So this fixes the issue, what I'd like to understand is why in most cases (like 99.9% of the time), the code was still working without the "joinedload" ? What could explain that the children object was loaded but at some point dropped
from the session ?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">I tried to reproduce the issue in mitaka (sorry didn't had a newton setup), but it appears I can’t reproduce it there ... I was hoping to reproduce it and make sure there is no latent bug in nova.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Has anybody seen this issue before or something similar ?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Thanks for the help,<o:p></o:p></p>
<p class="MsoNormal">/ludovic<o:p></o:p></p>
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