Detection of LVM physical volume which is not part of a VG

[Andreas Hasenack]

I have a case where swift-storage was deployed to a machine with two disks where /dev/sdb was *previously* part of an LVM group. Now it's not, but pvdisplay doesn't error:

# pvdisplay /dev/sdb
  "/dev/sdb" is a new physical volume of "465.76 GiB"
  --- NEW Physical volume ---
  PV Name /dev/sdb
  VG Name
  PV Size 465.76 GiB
  Allocatable NO
  PE Size 0
  Total PE 0
  Free PE 0
  Allocated PE 0
  PV UUID SBvNiL-msiR-OpWe-r57P-ag3H-GHxN-1BpQyi

Note the "VG Name". It's not part of any, but is_lvm_physical_volume() correctly returns "true".

list_lvm_volume_group(), however, fails parsing that output, returning "Name":

2014-05-09 16:36:13 INFO install Processing triggers for ureadahead (0.100.0-16) ...
2014-05-09 16:36:14 INFO install Volume group "Name" not found
2014-05-09 16:36:14 INFO install <open file '/proc/partitions', mode 'r' at 0x7ffde27a2db0>
2014-05-09 16:36:14 INFO install Traceback (most recent call last):
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/install", line 91, in <module>
2014-05-09 16:36:14 INFO install main()
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/install", line 85, in main
2014-05-09 16:36:14 INFO install hooks.execute(sys.argv)
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/charmhelpers/core/hookenv.py", line 381, in execute
2014-05-09 16:36:14 INFO install self._hooks[hook_name]()
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/install", line 45, in install
2014-05-09 16:36:14 INFO install setup_storage()
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/swift_storage_utils.py", line 178, in setup_storage
2014-05-09 16:36:14 INFO install clean_storage(dev)
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/misc_utils.py", line 81, in clean_storage
2014-05-09 16:36:14 INFO install deactivate_lvm_volume_group(block_device)
2014-05-09 16:36:14 INFO install File "/var/lib/juju/agents/unit-swift-storage-0/charm/hooks/charmhelpers/contrib/storage/linux/lvm.py", line 22, in deactivate_lvm_volume_group
2014-05-09 16:36:14 INFO install check_call(cmd)
2014-05-09 16:36:14 INFO install File "/usr/lib/python2.7/subprocess.py", line 540, in check_call
2014-05-09 16:36:14 INFO install raise CalledProcessError(retcode, cmd)
2014-05-09 16:36:14 INFO install subprocess.CalledProcessError: Command '['vgchange', '-an', 'Name']' returned non-zero exit status 5