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[Launchpad Bug Tracker <1915710@xxxxxxxxxxxxxxxxxx>]

[Expired for OpenStack Compute (nova) because there has been no activity
for 60 days.]

** Changed in: nova
       Status: Incomplete => Expired

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https://bugs.launchpad.net/bugs/1915710

Title:
  Doesn't download image from _base folder

Status in OpenStack Compute (nova):
  Expired

Bug description:
  Hello.

  Recently I encountered with strange behavior of nova while upgrading
  instance to a new flavor.

  I did:
  1. I created an instance from a previously made snapshot.
  2. After the instance has been successfully created, I deleted the snapshot from image storage.
  3. Created a new flavor with a bigger of disk space for the instance.
  4. I made resize the instance using a new flavor, with case when there are not enough resources on the src compute node and the instance started migrating to another compute node where there are enough resources.
  5. Once the instance disk has been completely copied to the new compute and the instance status has changed to VERITY_RESZIE, the instance disk (block device) remains the same size as in the old flavor. After confirming the upgrade, the disk remains the same size.

  In the logs I don't see any errors only a message like
  https://github.com/openstack/nova/blob/stable/queens/nova/virt/libvirt/driver.py#L7570
  and at the same time there is no image in the _base folder on the new
  compute node, the image remains on the old compute node until it is
  removed because its age is greater than the
  remove_unused_original_minimum_age_seconds in nova.conf.

  I made the following edits in the code:
  /usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py
  @@ -7676,13 +7676,13 @@
                         {'image_id': image_id, 'host': fallback_from_host},
                         instance=instance)
  -            def copy_from_host(target):
  +            def copy_from_host(target, image_id):
                   libvirt_utils.copy_image(src=target,
                                            dest=target,
                                            host=fallback_from_host,
                                            receive=True)
               image.cache(fetch_func=copy_from_host, size=size,
  -                        filename=filename)
  +                        filename=filename, image_id=image_id)

  And after that, everything worked as expected. The instance
  successfully migrated to dst compute during the upgrade, the disk grew
  according to the new flavor.

  But then I ran into one more issue, when the instance goes into the
  VERIFY_RESIZE status in the database already indicated that it is
  running on a different compute node and the image on the scr compute
  can be deleted due to remove_unused_original_minimum_age_seconds.
  After that, if you do revert, the image is not copied back to src
  compute.

  I made the following edits in the code:
  +++ /usr/lib/python2.7/dist-packages/nova/compute/manager.py
  @@ -7932,7 +7932,21 @@
                      'host': nodes}
           filtered_instances = objects.InstanceList.get_by_filters(context,
                                    filters, expected_attrs=[], use_slave=True)
  +        filters_migration_instances = {'status': [ 'finished', 'post-migrating'],
  +                    'source_compute': nodes,
  +                    'migration_type': 'resize'}
  +        migration_list_instances = objects.MigrationList.get_by_filters(context, filters=filters_migration_instances)
  +        if migration_list_instances:
  +            uuids = []
  +            for migration_instance in migration_list_instances:
  +                uuids.append(migration_instance['instance_uuid'])
  +            filters_by_instance = {'uuid': uuids}
  +            filtered_migration_instances = objects.InstanceList.get_by_filters(context, filters=filters_by_instance, expected_attrs=[], use_slave=True)
  +            filtered_instances = filtered_instances + filtered_migration_instances
           self.driver.manage_image_cache(context, filtered_instances)

  Thus, we will not delete the images of instances that are still in the
  VERIFY_RESIZE status.

  I would like to clarify if this is the basic behavior of nova or is it
  still a bug? Perhaps someone else has encountered similar problems.

  Environment
  OS - Ubuntu 16.04
  Linux compute1 4.15.0-122-generic #124~16.04.1-Ubuntu SMP Thu Oct 15 16:08:36 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux

  OpenStack release - Queens
  hypervisor - Libvirt + KVM

  dpkg -l | grep nova
  ii  nova-common                            2:17.0.12-0ubuntu1~sc1+0~20200110124932.9+xenial~1.gbp53edbd  all          OpenStack Compute - common files
  ii  nova-compute                           2:17.0.12-0ubuntu1~sc1+0~20200110124932.9+xenial~1.gbp53edbd  all          OpenStack Compute - compute node base
  ii  nova-compute-kvm                       2:17.0.12-0ubuntu1~sc1+0~20200110124932.9+xenial~1.gbp53edbd  all          OpenStack Compute - compute node (KVM)
  ii  nova-compute-libvirt                   2:17.0.12-0ubuntu1~sc1+0~20200110124932.9+xenial~1.gbp53edbd  all          OpenStack Compute - compute node libvirt support
  ii  python-nova                            2:17.0.12-0ubuntu1~sc1+0~20200110124932.9+xenial~1.gbp53edbd  all          OpenStack Compute Python libraries
  ii  python-nova-helper                     1.3+0~20190916150953.1+xenial~1.gbp807478                     amd64        utilites to manage nova and openstack
  ii  python-novaclient                      2:9.1.1-0ubuntu1~cloud0                                       all          client library for OpenStack Compute API - Python 2.7

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