Comment 5 for bug 1782714

And here are the volume details from the time when both attachments exist during live migration (metadata is still OK at this point):

{"volume": {"migration_status": null, "attachments": [{"server_id": "ff97a18d-cf12-4133-9df1-ee22a7304fc7", "attachment_id": "2f9944ba-9aa4-4e3f-a58f-7d60faae6ed5", "attached_at": "2018-07-25T06:15:42.000000", "host_name": "compute-1", "volume_id": "4394bec9-3b87-4a6e-b977-cb56719b0d2a", "device": "/dev/vdb", "id": "4394bec9-3b87-4a6e-b977-cb56719b0d2a"}, {"server_id": "ff97a18d-cf12-4133-9df1-ee22a7304fc7", "attachment_id": "e4a1918e-c3f1-429d-a006-84b0e27a9eea", "attached_at": "2018-07-25T06:28:17.000000", "host_name": "compute-3", "volume_id": "4394bec9-3b87-4a6e-b977-cb56719b0d2a", "device": "/dev/vdb", "id": "4394bec9-3b87-4a6e-b977-cb56719b0d2a"}], "links": [{"href": "https://10.7.25.34:8776/v3/b742e570d76d496e8d3d0cca8f2f039a/volumes/4394bec9-3b87-4a6e-b977-cb56719b0d2a", "rel": "self"}, {"href": "https://10.7.25.34:8776/b742e570d76d496e8d3d0cca8f2f039a/volumes/4394bec9-3b87-4a6e-b977-cb56719b0d2a", "rel": "bookmark"}], "availability_zone": "nova", "os-vol-host-attr:host": "controller-2@rbd#volumes_hdd", "encrypted": false, "updated_at": "2018-07-25T06:28:34.000000", "replication_status": null, "snapshot_id": null, "id": "4394bec9-3b87-4a6e-b977-cb56719b0d2a", "size": 1, "user_id": "545682b2c9b7466694bca136518a4568", "os-vol-tenant-attr:tenant_id": "b742e570d76d496e8d3d0cca8f2f039a", "os-vol-mig-status-attr:migstat": null, "metadata": {"attached_mode": "rw"}, "status": "in-use", "description": "", "multiattach": false, "source_volid": null, "consistencygroup_id": null, "os-vol-mig-status-attr:name_id": null, "name": "test_vol", "bootable": "false", "created_at": "2018-07-20T06:16:14.000000", "volume_type": null}}