[Bug 1896617] Re: [SRU] Creation of image (or live snapshot) from the existing VM fails if libvirt-image-backend is configured to qcow2 starting from Ussuri

Vladimir Grevtsev 1896617 at bugs.launchpad.net
Thu Sep 24 22:19:23 UTC 2020


However, the above has broken the new instance creation:

$ os server show demo-http -f yaml
OS-DCF:diskConfig: MANUAL
OS-EXT-AZ:availability_zone: ''
OS-EXT-SRV-ATTR:host: null
OS-EXT-SRV-ATTR:hypervisor_hostname: null
OS-EXT-SRV-ATTR:instance_name: instance-000002d8
OS-EXT-STS:power_state: NOSTATE
OS-EXT-STS:task_state: null
OS-EXT-STS:vm_state: error
OS-SRV-USG:launched_at: null
OS-SRV-USG:terminated_at: null
accessIPv4: ''
accessIPv6: ''
addresses: ''
config_drive: ''
created: '2020-09-24T22:14:20Z'
fault:
  code: 500
  created: '2020-09-24T22:14:48Z'
  details: "Traceback (most recent call last):\n  File \"/usr/lib/python3/dist-packages/nova/conductor/manager.py\"\
    , line 652, in build_instances\n    filter_properties, instances[0].uuid)\n  File\
    \ \"/usr/lib/python3/dist-packages/nova/scheduler/utils.py\", line 919, in populate_retry\n\
    \    raise exception.MaxRetriesExceeded(reason=msg)\nnova.exception.MaxRetriesExceeded:\
    \ Exceeded maximum number of retries. Exceeded max scheduling attempts 3 for instance\
    \ 711291b9-19fc-4e84-bc3e-423eda042630. Last exception: Cannot access storage\
    \ file '/var/lib/nova/instances/711291b9-19fc-4e84-bc3e-423eda042630/disk' (as\
    \ uid:64055, gid:117): Permission denied\n"
  message: 'Exceeded maximum number of retries. Exceeded max scheduling attempts 3
    for instance 711291b9-19fc-4e84-bc3e-423eda042630. Last exception: Cannot access
    storage file ''/var/lib/nova/instances/711291b9-19fc-4e84-bc3e-423eda042630/disk''
    (as uid:64055, gid:117'
flavor: m1.medium (3)
hostId: ''
id: 711291b9-19fc-4e84-bc3e-423eda042630
image: bionic-kvm (63727d33-4312-4c22-843e-2f5dfe4cb24c)
key_name: ubuntu-keypair
name: demo-http
project_id: 491dec5fd31d45108bd5fb8bb1486ffe
properties: ''
status: ERROR
updated: '2020-09-24T22:14:48Z'
user_id: 8170a7c8b627431eb37444dc504f84cb
volumes_attached: ''

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https://bugs.launchpad.net/bugs/1896617

Title:
  [SRU] Creation of image (or live snapshot) from the existing VM fails
  if libvirt-image-backend is configured to qcow2 starting from Ussuri

Status in OpenStack nova-compute charm:
  Invalid
Status in Ubuntu Cloud Archive:
  Triaged
Status in Ubuntu Cloud Archive ussuri series:
  Triaged
Status in Ubuntu Cloud Archive victoria series:
  Triaged
Status in OpenStack Compute (nova):
  Invalid
Status in nova package in Ubuntu:
  Triaged
Status in nova source package in Focal:
  Triaged
Status in nova source package in Groovy:
  Triaged

Bug description:
  [Impact]

  tl;dr

  1) creating the image from the existing VM fails if qcow2 image backend is used, but everything is fine if using rbd image backend in nova-compute.
  2) openstack server image create --name <name of the new image> <instance name or uuid> fails with some unrelated error:

  $ openstack server image create --wait 842fa12c-19ee-44cb-bb31-36d27ec9d8fc
  HTTP 404 Not Found: No image found with ID f4693860-cd8d-4088-91b9-56b2f173ffc7

  == Details ==

  Two Tempest tests ([1] and [2]) from the 2018.02 Refstack test lists
  [0] are failing with the following exception:

  49701867-bedc-4d7d-aa71-7383d877d90c
  Traceback (most recent call last):
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/api/compute/base.py", line 369, in create_image_from_server
      waiters.wait_for_image_status(client, image_id, wait_until)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/common/waiters.py", line 161, in wait_for_image_status
      image = show_image(image_id)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/lib/services/compute/images_client.py", line 74, in show_image
      resp, body = self.get("images/%s" % image_id)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/lib/common/rest_client.py", line 298, in get
      return self.request('GET', url, extra_headers, headers)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/lib/services/compute/base_compute_client.py", line 48, in request
      method, url, extra_headers, headers, body, chunked)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/lib/common/rest_client.py", line 687, in request
      self._error_checker(resp, resp_body)
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/lib/common/rest_client.py", line 793, in _error_checker
      raise exceptions.NotFound(resp_body, resp=resp)
  tempest.lib.exceptions.NotFound: Object not found
  Details: {'code': 404, 'message': 'Image not found.'}

  During handling of the above exception, another exception occurred:

  Traceback (most recent call last):
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/api/compute/images/test_images_oneserver.py", line 69, in test_create_delete_image
      wait_until='ACTIVE')
    File "/home/ubuntu/snap/fcbtest/14/.rally/verification/verifier-2d9cbf4d-fcbb-491d-848d-5137a9bde99e/repo/tempest/api/compute/base.py", line 384, in create_image_from_server
      image_id=image_id)
  tempest.exceptions.SnapshotNotFoundException: Server snapshot image d82e95b0-9c62-492d-a08c-5bb118d3bf56 not found.

  So far I was able to identify the following:

  1) https://github.com/openstack/tempest/blob/master/tempest/api/compute/images/test_images_oneserver.py#L69 invokes a "create image from server"
  2) It fails with the following error message in the nova-compute logs: https://pastebin.canonical.com/p/h6ZXdqjRRm/

  The same occurs if the "openstack server image create --wait" will be
  executed; however, according to
  https://docs.openstack.org/nova/ussuri/admin/migrate-instance-with-
  snapshot.html the VM has to be shut down before the image creation:

  "Shut down the source VM before you take the snapshot to ensure that
  all data is flushed to disk. If necessary, list the instances to view
  the instance name. Use the openstack server stop command to shut down
  the instance:"

  This step is definitely being skipped by the test (e.g it's trying to
  perform the snapshot on top of the live VM).

  FWIW, I'm using libvirt-image-backend: qcow2 in my nova-compute
  application params; and I was able to confirm that if the above
  parameter will be changed to "libvirt-image-backend: rbd", the tests
  will pass successfully.

  Also, there is similar issue I was able to find:
  https://bugs.launchpad.net/nova/+bug/1885418 but it doesn't have any
  useful information rather then confirmation of the fact that OpenStack
  Ussuri + libvirt backend has some problem with the live snapshotting.

  [0] https://refstack.openstack.org/api/v1/guidelines/2018.02/tests?target=platform&type=required&alias=true&flag=false
  [1] tempest.api.compute.images.test_images_oneserver.ImagesOneServerTestJSON.test_create_delete_image[id-3731d080-d4c5-4872-b41a-64d0d0021314]
  [2] tempest.api.compute.images.test_images_oneserver.ImagesOneServerTestJSON.test_create_image_specify_multibyte_character_image_name[id-3b7c6fe4-dfe7-477c-9243-b06359db51e6]

  
  [Test Case]
  deploy/configure openstack, using juju here
  create openstack instance
  openstack server image create --wait <instance-uuid>
  successful if fixed; fails with permissions error if not fixed

  [Regression Potential]
  This actually reverts the nova group members to what they used to be prior to the focal version of the packages. If there is a regression in this fix it would likely result in a permissions issue.

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