Glossary¶
- agent¶
Software service running on the OpenStack infrastructure measuring usage and sending the results to any number of target using the publisher.
- billing¶
Billing is the process to assemble bill line items into a single per customer bill, emitting the bill to start the payment collection.
- bus listener agent¶
Bus listener agent which takes events generated on the Oslo notification bus and transforms them into Ceilometer samples. This is the preferred method of data collection.
- polling agent¶
Software service running either on a central management node within the OpenStack infrastructure or compute node measuring usage and sending the results to a queue.
- notification agent¶
The different OpenStack services emit several notifications about the various types of events. The notification agent consumes them from respective queues and filters them by the event_type.
- data store¶
Storage system for recording data collected by ceilometer.
- meter¶
The measurements tracked for a resource. For example, an instance has a number of meters, such as duration of instance, CPU time used, number of disk io requests, etc. Three types of meters are defined in ceilometer:
Cumulative: Increasing over time (e.g. disk I/O)
Gauge: Discrete items (e.g. floating IPs, image uploads) and fluctuating values (e.g. number of Swift objects)
Delta: Incremental change to a counter over time (e.g. bandwidth delta)
- metering¶
Metering is the process of collecting information about what, who, when and how much regarding anything that can be billed. The result of this is a collection of “tickets” (a.k.a. samples) which are ready to be processed in any way you want.
- notification¶
A message sent via an external OpenStack system (e.g Nova, Glance, etc) using the Oslo notification mechanism [1]. These notifications are usually sent to and received by Ceilometer through the notifier RPC driver.
- non-repudiable¶
“Non-repudiation refers to a state of affairs where the purported maker of a statement will not be able to successfully challenge the validity of the statement or contract. The term is often seen in a legal setting wherein the authenticity of a signature is being challenged. In such an instance, the authenticity is being “repudiated”.” (Wikipedia, [2])
- project¶
The OpenStack tenant or project.
- polling agents¶
The polling agent is collecting measurements by polling some API or other tool at a regular interval.
- publisher¶
The publisher is publishing samples to a specific target.
- push agents¶
The push agent is the only solution to fetch data within projects, which do not expose the required data in a remotely usable way. This is not the preferred method as it makes deployment a bit more complex having to add a component to each of the nodes that need to be monitored.
- rating¶
Rating is the process of analysing a series of tickets, according to business rules defined by marketing, in order to transform them into bill line items with a currency value.
- resource¶
The OpenStack entity being metered (e.g. instance, volume, image, etc).
- sample¶
Data sample for a particular meter.
- source¶
The origin of metering data. This field is set to “openstack” by default. It can be configured to a different value using the sample_source field in the ceilometer.conf file.
- user¶
An OpenStack user.
