Doesn't download image from _base folder

[Dmitriy]

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

[Uggla (rene-ribaud)]

This bug has been open for quite a long time without activities. So I really apologize if you cannot have the support required.
However, the bug was on older version, which is out of support now.
I propose closing this bug unless you still have it, and you can reproduce it on a supported release. Please provide the new info and set this bug back to new.

[Launchpad Janitor (janitor)]

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