How to trigger Qinling function in Aodh

2018-05-13

本博客所有文章采用的授权方式为 自由转载-非商用-非衍生-保持署名 ,转载请务必注明出处,谢谢。

声明:
本博客欢迎转发,但请保留原作者信息!
新浪微博:@Lingxian_kong;
博客地址:孔令贤的博客;
微信公众号:飞翔的尘埃;
内容系本人学习、研究和总结,如有雷同,实属荣幸!

Aodh is the Alarming service project in OpenStack that enables the ability to trigger actions based on defined rules against metric or event data collected by Ceilometer or Gnocchi.

We can use Aodh alarm to trigger Qinling functions by some cloud events, e.g. when an instance is created in this guide.

Step1: Create webhook for the function in Qinling

Webhook in Qinling allows to trigger the function without providing OpenStack credentials, the webhook URL is only known by the function owner.

Suppose we have a simple Python function that prints out a string:

$ cat ~/functions/hello_world.py
def main(name='World', **kwargs):
    ret = 'Hello, %s' % name
    return ret

Create a function using the Python script:

$ RUNTIME_ID=bd516a15-3787-4652-938b-e25665c376e6
$ openstack function create --runtime $RUNTIME_ID \
    --entry hello_world.main \
    --file ~/functions/hello_world.py
+-------------+-------------------------------------------------------------------------+
| Field       | Value                                                                   |
+-------------+-------------------------------------------------------------------------+
| id          | 5b25e0ea-7f8d-487a-bce6-f6a2556a1e3f                                    |
| name        | None                                                                    |
| description | None                                                                    |
| count       | 0                                                                       |
| code        | {u'source': u'package', u'md5sum': u'9bad2959cafc9d89684fe7a336de9927'} |
| runtime_id  | bd516a15-3787-4652-938b-e25665c376e6                                    |
| entry       | hello_world.main                                                        |
| project_id  | 360d69d06890407eab1a44573c1f3776                                        |
| created_at  | 2018-05-13 06:58:13.208421                                              |
| updated_at  | None                                                                    |
+-------------+-------------------------------------------------------------------------+

Create a webhook for the function:

$ function_id=5b25e0ea-7f8d-487a-bce6-f6a2556a1e3f
$ openstack webhook create $function_id
+-------------+-------------------------------------------------------------------------------+
| Field       | Value                                                                         |
+-------------+-------------------------------------------------------------------------------+
| id          | a5f82898-a4c3-4104-ad2d-40fbafbe8857                                          |
| function_id | 5b25e0ea-7f8d-487a-bce6-f6a2556a1e3f                                          |
| description | None                                                                          |
| project_id  | 360d69d06890407eab1a44573c1f3776                                              |
| created_at  | 2018-05-13 06:59:20.616092                                                    |
| updated_at  | None                                                                          |
| webhook_url | http://10.0.0.14:7070/v1/webhooks/a5f82898-a4c3-4104-ad2d-40fbafbe8857/invoke |
+-------------+-------------------------------------------------------------------------------+

The webhook_url could be used to trigger the function without any authentication. Make note of this URL, as it will be used as the alarm action when we create the alarm in Aodh.

Step2: Create an event alarm in Aodh

In Aodh, we only need to define an alarm that will be triggered by the event compute.instance.create (Nova will emit the event when there is a new VM created), using the webhook URL from Step1.

$ webhook_url=http://10.0.0.14:7070/v1/webhooks/a5f82898-a4c3-4104-ad2d-40fbafbe8857/invoke
$ aodh alarm create --name qinling-alarm \
    --type event --alarm-action $webhook_url \
    --repeat-actions false --event-type compute.instance.create
+---------------------------+------------------------------------------------------------------------------------+
| Field                     | Value                                                                              |
+---------------------------+------------------------------------------------------------------------------------+
| alarm_actions             | [u'http://10.0.0.14:7070/v1/webhooks/a5f82898-a4c3-4104-ad2d-40fbafbe8857/invoke'] |
| alarm_id                  | 1f85edea-a8a6-47ba-b1f5-9e3ac7ee61dc                                               |
| description               | Alarm when compute.instance.create event occurred.                                 |
| enabled                   | True                                                                               |
| event_type                | compute.instance.create                                                            |
| insufficient_data_actions | []                                                                                 |
| name                      | qinling-alarm                                                                      |
| ok_actions                | []                                                                                 |
| project_id                | 360d69d06890407eab1a44573c1f3776                                                   |
| query                     |                                                                                    |
| repeat_actions            | False                                                                              |
| severity                  | low                                                                                |
| state                     | insufficient data                                                                  |
| state_reason              | Not evaluated yet                                                                  |
| state_timestamp           | 2018-05-13T07:13:03.631059                                                         |
| time_constraints          | []                                                                                 |
| timestamp                 | 2018-05-13T07:13:03.631059                                                         |
| type                      | event                                                                              |
| user_id                   | 26d9ec1da7fc4756b1940e69292565c2                                                   |
+---------------------------+------------------------------------------------------------------------------------+

Step3: Simulate an event trigger

For testing purpose, I wrote a Python script to generate an event for this Aodh alarm so that we don’t need to install and config Nova and Ceilometer service. The script sends a notification with event_type as compute.instance.create to Aodh service directly. The script was tested in a default Devstack environment.

First, create a config file for the script:

$ mkdir -p /etc/lingxian
$ cat <<EOF > /etc/lingxian/lingxian.conf
[oslo_messaging_rabbit]
rabbit_userid = stackrabbit
rabbit_password = password
EOF

Download the script, modify the conf_file and project_id, the project_id should be the same with the project who created the alarm. Run the script:

$ curl -sSO https://raw.githubusercontent.com/lingxiankong/qinling_utils/master/aodh_notifier_simulator.py
$ python aodh_notifier_simulator.py

Now the alarm should be triggered, and the webhook is invoked. Check the alarm history, we could see the alarm state transition:

$ alarm_id=1f85edea-a8a6-47ba-b1f5-9e3ac7ee61dc
$ aodh alarm-history show $alarm_id -f yaml
- detail: '{"transition_reason": "Event <id=ac6ce4ae-546a-47cc-a0cb-ad1bae44ca61,event_type=compute.instance.create>
    hits the query <query=[]>.", "state": "alarm"}'
  event_id: 3250eed6-edaf-41e8-bfa6-42b060f96e75
  timestamp: '2018-05-13T08:34:47.977951'
  type: state transition
- detail: '{"state_reason": "Not evaluated yet", "user_id": "26d9ec1da7fc4756b1940e69292565c2",
    "name": "qinling-alarm", "state": "insufficient data", "timestamp": "2018-05-13T07:13:03.631059",
    "description": "Alarm when compute.instance.create event occurred.", "enabled":
    true, "state_timestamp": "2018-05-13T07:13:03.631059", "rule": {"query": [], "event_type":
    "compute.instance.create"}, "alarm_id": "1f85edea-a8a6-47ba-b1f5-9e3ac7ee61dc",
    "time_constraints": [], "insufficient_data_actions": [], "repeat_actions": false,
    "ok_actions": [], "project_id": "360d69d06890407eab1a44573c1f3776", "type": "event",
    "alarm_actions": ["http://10.0.0.14:7070/v1/webhooks/a5f82898-a4c3-4104-ad2d-40fbafbe8857/invoke"],
    "severity": "low"}'
  event_id: 231ca53e-5d74-4191-8136-b332d2d91f1a
  timestamp: '2018-05-13T07:13:03.631059'
  type: creation

Check the function execution in Qinling:

$ function_id=5b25e0ea-7f8d-487a-bce6-f6a2556a1e3f
$ openstack function execution list --filter function_id=$function_id -f yaml
- Created_at: '2018-05-13 08:34:49'
  Description: Created by Webhook a5f82898-a4c3-4104-ad2d-40fbafbe8857
  Function_id: 5b25e0ea-7f8d-487a-bce6-f6a2556a1e3f
  Id: 41b351fa-a96b-4d86-ba77-33f7bca3dad1
  Input: '{"current": "alarm", "alarm_id": "1f85edea-a8a6-47ba-b1f5-9e3ac7ee61dc",
    "reason": "Event <id=ac6ce4ae-546a-47cc-a0cb-ad1bae44ca61,event_type=compute.instance.create>
    hits the query <query=[]>.", "severity": "low", "reason_data": {"type": "event",
    "event": {"event_type": "compute.instance.create", "traits": [["project_id", 1,
    "360d69d06890407eab1a44573c1f3776"], ["service", 1, "nova"], ["vm_name", 1, "new_instance"],
    ["vm_id", 1, "ba2b30a0-1b14-4ad4-9a66-f24ece912cad"]], "message_signature": "bcfb59e386d5375dbb7ded9910900a98536f168d377f52ae7ffd89159c0019f5",
    "raw": {}, "generated": "2017-10-03T10:02:38.305378", "message_id": "ac6ce4ae-546a-47cc-a0cb-ad1bae44ca61"}},
    "alarm_name": "qinling-alarm", "previous": "insufficient data"}'
  Project_id: 360d69d06890407eab1a44573c1f3776
  Result: '{"duration": 0.084, "output": "Hello, World"}'
  Status: success
  Sync: false
  Updated_at: '2018-05-13 08:34:53'

Conclusion

Although a Qinling function can be invoked on demand, trigger the function according to the cloud events automatically(i.e. event-driven) can bring more power to your function and make your whole application more efficient and cost effective.

文章赞赏

赞赏码

文章评论

comments powered by Disqus


章节列表