Ceilometer is a data collection service. It normalizes data across OpenStack and can be configured to persist the normalized data to multiple services. Gnocchi is designed to store time-series measurement data. Panko is intended to capture event data. Lastly, Aodh provides alarming functionality.
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 publishers 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. Edit the pipeline.yaml and event_pipeline.yaml to include multiple publishers:
---
sources:
- name: event_source
events:
- "*"
sinks:
- event_sink
sinks:
- name: event_sink
publishers:
- gnocchi://
- database://