Ironic Notifications

https://blueprints.launchpad.net/ceilometer/+spec/ironic-notifications

Work is in progress to get Ironic to emit notifications from data provided by IPMI sensors (such as cpu temp and voltage). Ceilometer needs to be updated to consume, transform and record these notifications.

Problem description

The Ironic project is doing work to emit notifications on the message bus containing IPMI sensor data. If Ceilometer processes these notifications other services will be able use queries and alarms to monitor and scale as required.

It is not possible to simply dump a message on the bus and for Ceilometer to handle it. Instead a notification plugin is required, in Ceilometer, to hear notifications at an exchange and topic and transform them into samples.

Proposed change

Add a new notification plugin for Ironic to transform sensor data into samples, using existing NotficationBase implementations as a model. To do this effectively a complete sample of the expected sensor data is required to determine the relevant types of samples.

Alternatives

Handling notifications is the standard and preferred method for gathering data into Ceilometer. The other option is polling which has known scalability issues, including over-frequent polling of IPMI. If Ironic is sending notifications it can continue to own the credentials for the IPMI access and also control the cadence with which sensors are polled. Using notifications also allows other services to consume the sensor data.

Data model impact

None.

REST API impact

There will be additional valid values in query parameters but no changes to API endpoints.

Security impact

None.

Pipeline impact

Unknown. The data being provided by the Ironic notifier is still being decided. Only when it is available will it be possible to determine what, if any, transformations may be usefully done in the pipeline.

Other end user impact

None.

Performance/Scalability Impacts

No new impacts. Pre-existing concerns with capacity at the notification and storage handling layers remain.

Other deployer impact

None.

Developer impact

None.

Implementation

Assignee(s)

Who is leading the writing of the code? Or is this a blueprint where you’re throwing it out there to see who picks it up?

If more than one person is working on the implementation, please designate the primary author and contact.

Primary assignee:
chdent
Other contributors:
whaom
Ongoing maintainer:
chdent

Work Items

  • Establish expected data.
  • Create tests of transformation of sensordata to samples.
  • Create notification plugin to consume sensordata.
  • Create tests of notifications across fake bus.
  • Create sample query tests.

Future lifecycle

In the future new types of notifications are expected from the Ironic controller. These will need to be handled either by additional notification plugins or (hopefully) generic notification handling. The Ceilometer team will be responsible for collaborating with the Ironic team to ensure these are handled smoothly.

Dependencies

The primary dependency is work described in an Ironic spec. Once that is implemented, notifications will be present on the bus.

Testing

In addition to unit tests, Tempest tests which confirm that Ceilometer consumes notifications produced by Ironic would be useful. Such tests depend on there being a tool to provide sensor data in the testing environment. Such a tool would be similar to bm_poseur which fakes baremetal instances in devstack. In the event that such a tool is not available as long as the sample data used in unit tests is sufficiently representative then the tests themselves ought to be as well.

Documentation Impact

The added metrics will need to be documented in the measurements section.

References