.. Copyright 2012 New Dream Network (DreamHost) Copyright 2013 eNovance Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ========== Glossary ========== .. glossary:: agent Software service running on the OpenStack infrastructure measuring usage and sending the results to the :term:`collector`. alarm An action triggered whenever a meter reaches a certain threshold. API server HTTP REST API service for ceilometer. ceilometer From Wikipedia [#]_: A ceilometer is a device that uses a laser or other light source to determine the height of a cloud base. central agent Software service running on a central management node within the OpenStack infrastructure measuring usage and sending the results to the :term:`collector`. collector Software service running on the OpenStack infrastructure monitoring notifications from other OpenStack components and samples from the ceilometer agent and recording the results in the database. compute agent Software service running on a compute node within the OpenStack infrastructure measuring usage and sending the results to the :term:`collector`. 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) notification A message sent via an external OpenStack system (e.g Nova, Glance, etc) using the Oslo notification mechanism [#]_. These notifications are usually sent to and received by Ceilometer through the notifier RPC driver. non-repudiable From Wikipedia [#]_: 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". project The OpenStack tenant or project. 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. .. [#] http://en.wikipedia.org/wiki/Ceilometer .. [#] https://git.openstack.org/cgit/openstack/ceilometer/tree/ceilometer/openstack/common/notifier .. [#] http://en.wikipedia.org/wiki/Non-repudiation