Traceback (most recent call last):
  File "./hooks/leader-settings-changed", line 725, in <module>
    hooks.execute(sys.argv)
  File "/var/lib/juju/agents/unit-ceph-mon-0/charm/hooks/charmhelpers/core/hookenv.py", line 798, in execute
    self._hooks[hook_name]()
  File "./hooks/leader-settings-changed", line 389, in mon_relation
    notify_osds()
  File "./hooks/leader-settings-changed", line 400, in notify_osds
    osd_relation(relid=relid, unit=unit)
  File "./hooks/leader-settings-changed", line 453, in osd_relation
    notify_client()
  File "./hooks/leader-settings-changed", line 413, in notify_client
    client_relation_changed(relid, unit)
  File "./hooks/leader-settings-changed", line 601, in client_relation_changed
    unit_id = remote_unit().replace('/', '-')
AttributeError: 'NoneType' object has no attribute 'replace'

root@juju-440d80-ceph-0:/var/lib/juju/agents/unit-ceph-mon-0/charm# grep -A4 "def remote_unit" /var/lib/juju/agents/unit-ceph-mon-0/charm/hooks/charmhelpers/core/hookenv.py
def remote_unit():
    """The remote unit for the current relation hook"""
    return os.environ.get('JUJU_REMOTE_UNIT', None)


root@juju-440d80-ceph-0:/var/lib/juju/agents/unit-ceph-mon-0/charm# env | grep JUJU_REMOTE_UNIT
root@juju-440d80-ceph-0:/var/lib/juju/agents/unit-ceph-mon-0/charm#