Comment 0 for bug 1327218

Example of this here:

http://logs.openstack.org/33/97233/1/check/check-grenade-dsvm/f7b8a11/logs/old/screen-n-cpu.txt.gz?level=TRACE#_2014-06-02_14_13_51_125

   File "/opt/stack/old/nova/nova/compute/manager.py", line 4153, in _detach_volume
     connection_info = jsonutils.loads(bdm.connection_info)
   File "/opt/stack/old/nova/nova/openstack/common/jsonutils.py", line 164, in loads
     return json.loads(s)
   File "/usr/lib/python2.7/json/__init__.py", line 326, in loads
     return _default_decoder.decode(s)
   File "/usr/lib/python2.7/json/decoder.py", line 366, in decode
     obj, end = self.raw_decode(s, idx=_w(s, 0).end())
 TypeError: expected string or buffer

and this was in grenade with stable/icehouse nova commit 7431cb9

There's nothing unusual about the test which triggers this - simply attaches a volume to an instance, waits for it to show up in the instance and then tries to detach it

logstash query for this:

  message:"Exception during message handling" AND message:"expected string or buffer" AND message:"connection_info = jsonutils.loads(bdm.connection_info)" AND filename:"logs/screen-n-cpu.txt"

but it seems to be very rare