watcher-specs/specs/ussuri/approved/event-driven-optimization-based.rst

Event-driven optimization based

https://blueprints.launchpad.net/watcher/+spec/event-driven-optimization-based

Problem description

Watcher has provided ONESHOT and CONTINUOUS audit. ONESHOT audit executes the optimization only once after being launched. CONTINUOUS audit executes the optimization periodly. But there is no way to react to the changes of system, for example an alarm event.

Use Cases

As a user of Watcher, I want to execute optimization as soon as possible when there are alarms in the system.

Proposed change

Many monitor system, such as aodh, can set webhook as alarm action, a POST request will be sent if the alarm is trigered. About the authentication of the POST request, Aodh's alarm action can set prefix trust to add a X-Auth-Token header to the request url. Watcher add a new config option enable_webhooks_auth to decide whether to enable webhook authentication, the default is True. Watcher add the mechanism for receiving and handling alarm events.

Here is the summary processing: User creates an event based audit, a new audit type, named EVENT, is needed. Creating alarm with Watcher webhook and audit uuid in the monitor system such as aodh. When the alarm is trigered, Watcher will receive the event with audit uuid. Watcher executes the audit and creates actionplan.

Alternatives

CONTINUOUS audit can be used to satisfy the purpose but this will increase the workload.

Data model impact

None

REST API impact

Add a new webhook API

• /v1/webhooks/{audit_ident}
  • Triggers an event based audit, audit_ident is uuid or name of the audit. Does not perform verification of authentication token.
  • Method type: POST
  • Normal http response code: 202(Accepted)
  • Expected error http response code: 400, 404(Not Found)

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

None

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

licanwei

Work Items

• Add a new audit type, named EVENT
• Add a new webhook API
• processing for event based audit

Dependencies

None

Testing

• Unit tests for the new feature

Documentation Impact

• Add documentation about how to use the new feature

References

https://docs.openstack.org/aodh/latest/

History

Revisions

Release Name	Description
Ussuri	Introduced