Cannot create or list ceilometer alarms

Issue

• Unable to create Ceilometer alarms

[root@cloudctl01 ~(openstack_admin)]# ceilometer alarm-threshold-create --name monitor-image --description 'monitor image' --meter-name image.update --threshold 1 --comparison-operator ge --statistic count --period 60 --evaluation-period 1 --alarm-action 'log://'
+---------------------------+--------------------------------------+
| Property                  | Value                                |
+---------------------------+--------------------------------------+
| alarm_actions             | [u'log://']                          |
| alarm_id                  | 4f232344-b96f-406d-9ba7-67830c707740 |
| comparison_operator       | ge                                   |
| description               | monitor image                        |
| enabled                   | True                                 |
| evaluation_periods        | 1                                    |
| exclude_outliers          | False                                |
| insufficient_data_actions | []                                   |
| meter_name                | image.update                         |
| name                      | monitor-image                        |
| ok_actions                | []                                   |
| period                    | 60                                   |
| project_id                |                                      |
| query                     |                                      |
| repeat_actions            | False                                |
| severity                  | low                                  |
| state                     | insufficient data                    |
| statistic                 | count                                |
| threshold                 | 1.0                                  |
| type                      | threshold                            |
| user_id                   | 27f895b2afa340d8976f5e19a19f4792     |
+---------------------------+--------------------------------------+

• But ceilometer alarm-list doesn't list alarms properly:

[root@cloudctl01 ~(openstack_admin)]# ceilometer alarm-list
Invalid input for field/attribute severity. Value: 'None'. Value should be one of: moderate, critical, low (HTTP 400) (Request-ID: req-66558227-fe0a-4f40-891f-9e6a3bcdde3e)

• Trace logs:

==> /var/log/ceilometer/alarm-evaluator.log <==
2015-12-29 07:43:14.472 51382 ERROR ceilometer.alarm.service [-] alarm evaluation cycle failed
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service Traceback (most recent call last):
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometer/alarm/service.py", line 93, in _evaluate_assigned_alarms
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     alarms = self._assigned_alarms()
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometer/alarm/service.py", line 174, in _assigned_alarms
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     'value': True}])
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/v2/alarms.py", line 77, in list
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     return self._list(options.build_url(self._path(), q))
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/common/base.py", line 68, in _list
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     resp = self.api.get(url)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/openstack/common/apiclient/client.py", line 355, in get
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     return self.client_request("GET", url, **kwargs)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/openstack/common/apiclient/client.py", line 345, in client_request
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     self, method, url, **kwargs)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/openstack/common/apiclient/client.py", line 261, in client_request
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     method, self.concat_url(endpoint, url), **kwargs)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service   File "/usr/lib/python2.7/site-packages/ceilometerclient/openstack/common/apiclient/client.py", line 201, in request
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service     raise exceptions.from_response(resp, method, url)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service BadRequest: Invalid input for field/attribute severity. Value: 'None'. Value should be one of: moderate, critical, low (HTTP 400) (Request-ID: req-6ca25add-8fab-42ad-88a8-d68dc715ceec)
2015-12-29 07:43:14.472 51382 TRACE ceilometer.alarm.service