Comment 0 for bug 1878752

juju run-action --wait ceph-osd/0 add-disk osd-devices=/dev/disk/by-dname/bcache2

unit-ceph-osd-0:
  UnitId: ceph-osd/0
  id: "5"
  message: exit status 1
  results:
    ReturnCode: 1
    Stderr: |
      partx: /dev/disk/by-dname/bcache2: failed to read partition table
        Failed to find physical volume "/dev/bcache1".
        Failed to find physical volume "/dev/bcache1".
        Device /dev/disk/by-dname/bcache2 not found.
      Traceback (most recent call last):
        File "/var/lib/juju/agents/unit-ceph-osd-0/charm/actions/add-disk", line 79, in <module>
          request = add_device(request=request,
        File "/var/lib/juju/agents/unit-ceph-osd-0/charm/actions/add-disk", line 34, in add_device
          charms_ceph.utils.osdize(device_path, hookenv.config('osd-format'),
        File "lib/charms_ceph/utils.py", line 1497, in osdize
          osdize_dev(dev, osd_format, osd_journal,
        File "lib/charms_ceph/utils.py", line 1570, in osdize_dev
          cmd = _ceph_volume(dev,
        File "lib/charms_ceph/utils.py", line 1705, in _ceph_volume
          cmd.append(_allocate_logical_volume(dev=dev,
        File "lib/charms_ceph/utils.py", line 1965, in _allocate_logical_volume
          lvm.create_lvm_volume_group(vg_name, pv_dev)
        File "hooks/charmhelpers/contrib/storage/linux/lvm.py", line 104, in create_lvm_volume_group
          check_call(['vgcreate', volume_group, block_device])
        File "/usr/lib/python3.8/subprocess.py", line 364, in check_call
          raise CalledProcessError(retcode, cmd)
      subprocess.CalledProcessError: Command '['vgcreate', 'ceph-911bc34b-4634-4ebd-a055-876b978d0b0a', '/dev/disk/by-dname/bcache2']' returned non-zero exit status 5.
    Stdout: |2
        Physical volume "/dev/disk/by-dname/bcache2" successfully created.
  status: failed
  timing:
    completed: 2020-05-15 06:04:41 +0000 UTC
    enqueued: 2020-05-15 06:04:30 +0000 UTC
    started: 2020-05-15 06:04:39 +0000 UTC

The same action on the /dev/bcacheX device succeeds - looks like some sort of behaviour break in Ubuntu.