Unmapping image fails on ceph 13.2.0+

[Stephen Finucane]

When nova fails to attach a volume to an instance, it will attempt to disconnect it. On a compute node with ceph 14.x, this fails:

  Traceback (most recent call last):
    File "/usr/lib/python3.6/site-packages/nova/virt/block_device.py", line 582, in _volume_attach
      device_type=self['device_type'], encryption=encryption)
    File "/usr/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 1806, in attach_volume
      encryption=encryption)
    File "/usr/lib/python3.6/site-packages/nova/virt/libvirt/driver.py", line 1594, in _connect_volume
      vol_driver.disconnect_volume(connection_info, instance)
    File "/usr/lib/python3.6/site-packages/nova/virt/libvirt/volume/net.py", line 96, in disconnect_volume
      self.connector.disconnect_volume(connection_info['data'], None)
    File "/usr/lib/python3.6/site-packages/os_brick/utils.py", line 150, in trace_logging_wrapper
      result = f(*args, **kwargs)
    File "/usr/lib/python3.6/site-packages/os_brick/initiator/connectors/rbd.py", line 248, in disconnect_volume
      root_device = self._find_root_device(connection_properties)
    File "/usr/lib/python3.6/site-packages/os_brick/initiator/connectors/rbd.py", line 229, in _find_root_device
      for index, mapping in jsonutils.loads(out).items():
  AttributeError: 'list' object has no attribute 'items'

The culprit appear to have been a change introduced in ceph v13.2.0 (Mimic). From [1].

  The rbd CLI’s showmapped JSON and XML output has changed.

This specific change appear to have been [2].

There appear to be additional issues here with regards to why the *attach* failed, but I can track those separately.

[1] https://docs.ceph.com/docs/master/releases/mimic/#upgrade-compatibility-notes
[2] https://github.com/ceph/ceph/commit/de97a3be483242eab14175a3cc3408df34d5c19a

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/736566

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/736566
Committed: https://git.openstack.org/cgit/openstack/os-brick/commit/?id=a87ef7bbabc80bf7f2d078764986aea2cbb90aa5
Submitter: Zuul
Branch: master

commit a87ef7bbabc80bf7f2d078764986aea2cbb90aa5
Author: Stephen Finucane <email address hidden>
Date: Thu Jun 18 11:33:33 2020 +0100

    rbd: Support 'rbd showmapped' output from ceph 13.2.0+

    Ceph 13.2.0 changed [1] the JSON and XML output format for the 'rbd
    showmapped' command, from a object keyed by device ID to a list of
    device objects. Handle this change.

    Change-Id: I55bc70437d41da3a32b8440d00c139805b8be256
    Signed-off-by: Stephen Finucane <email address hidden>
    Closes-Bug: #1884052

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/ussuri
Review: https://review.opendev.org/738235

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/738235
Committed: https://git.openstack.org/cgit/openstack/os-brick/commit/?id=bf0faeaea4626f7dee37a672da7e3f175b958086
Submitter: Zuul
Branch: stable/ussuri

commit bf0faeaea4626f7dee37a672da7e3f175b958086
Author: Stephen Finucane <email address hidden>
Date: Thu Jun 18 11:33:33 2020 +0100

    rbd: Support 'rbd showmapped' output from ceph 13.2.0+

    Ceph 13.2.0 changed [1] the JSON and XML output format for the 'rbd
    showmapped' command, from a object keyed by device ID to a list of
    device objects. Handle this change.

    Change-Id: I55bc70437d41da3a32b8440d00c139805b8be256
    Signed-off-by: Stephen Finucane <email address hidden>
    Closes-Bug: #1884052
    (cherry picked from commit a87ef7bbabc80bf7f2d078764986aea2cbb90aa5)

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/train
Review: https://review.opendev.org/748590

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/748590
Committed: https://git.openstack.org/cgit/openstack/os-brick/commit/?id=ba9d47a9b585dd619af857b6ea43dfb2ef04029c
Submitter: Zuul
Branch: stable/train

commit ba9d47a9b585dd619af857b6ea43dfb2ef04029c
Author: Stephen Finucane <email address hidden>
Date: Thu Jun 18 11:33:33 2020 +0100

    rbd: Support 'rbd showmapped' output from ceph 13.2.0+

    Ceph 13.2.0 changed [1] the JSON and XML output format for the 'rbd
    showmapped' command, from a object keyed by device ID to a list of
    device objects. Handle this change.

    Change-Id: I55bc70437d41da3a32b8440d00c139805b8be256
    Signed-off-by: Stephen Finucane <email address hidden>
    Closes-Bug: #1884052
    (cherry picked from commit a87ef7bbabc80bf7f2d078764986aea2cbb90aa5)
    (cherry picked from commit bf0faeaea4626f7dee37a672da7e3f175b958086)