Gnocchi represents a fundamental change in how data is represented and stored. Installation and configuration can be found in Installing Manually. Differences between APIs can be found here.
There currently exists no migration tool between the services. To transition to Gnocchi, multiple dispatchers can be enabled in the Collector to capture data in both the native Ceilometer database and Gnocchi. This will allow you to test Gnocchi and transition to it fully when comfortable. The following should be included in addition to the required configurations for each backend:
[DEFAULT]
meter_dispatchers=database
meter_dispatchers=gnocchi
event_dispatchers=gnocchi
In somes cases, it is possible to disable keystone authentication for Gnocchi to remove the overhead of token creation/verification when request authentication doesn’t matter. This will increase the performance of Gnocchi.
Example of configuration:
[dispatcher_gnocchi]
auth_section=service_credentials_gnocchi
[service_credentials_gnocchi]
auth_type=gnocchi-noauth
roles = admin
user_id = <ceilometer_user_id>
project_id = <ceilometer_project_id>
endpoint = <gnocchi_endpoint>
Note
Ceilometer’s native database capabilities is intended for post processing and auditing purposes where responsiveness is not a requirement. It captures the full fidelity of each datapoint and thus is not designed for low latency use cases. For more responsive use cases, it’s recommended to store data in an alternative source such as Gnocchi. Please see Moving from Ceilometer to Gnocchi to find more information.
Note
As of Liberty, alarming support, and subsequently its database, is handled by Aodh.
Note
As of Newton, event storage support is handled by Panko.
The following is a table indicating the status of each database drivers:
| Driver | API querying | API statistics |
|---|---|---|
| MongoDB | Yes | Yes |
| MySQL | Yes | Yes |
| PostgreSQL | Yes | Yes |
| HBase | Yes | Yes, except groupby & selectable aggregates |