ceilometer/doc/source/contributor/overview.rst

Overview

Objectives

The Ceilometer project was started in 2012 with one simple goal in mind: to provide an infrastructure to collect any information needed regarding OpenStack projects. It was designed so that rating engines could use this single source to transform events into billable items which we label as "metering".

As the project started to come to life, collecting an increasing number of meters across multiple projects, the OpenStack community started to realize that a secondary goal could be added to Ceilometer: become a standard way to meter, regardless of the purpose of the collection. This data can then be pushed to any set of targets using provided publishers mentioned in pipeline-publishers section.

Metering

If you divide a billing process into a 3 step process, as is commonly done in the telco industry, the steps are:

1. Metering
2. Rating
3. Billing

Ceilometer's initial goal was, and still is, strictly limited to step one. This is a choice made from the beginning not to go into rating or billing, as the variety of possibilities seemed too large for the project to ever deliver a solution that would fit everyone's needs, from private to public clouds. This means that if you are looking at this project to solve your billing needs, this is the right way to go, but certainly not the end of the road for you.