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Glossary of Centreon concepts


When a user acknowledges a resource in Centreon, they notify their teams that they are aware of the incident and that they will take action to resolve it.

When a resource is acknowledged, notifications are stopped, and the resource is highlighted yellow in monitoring screens.

Acknowledging a resource does not mean that the incident is over. It will be over when the resource is back to its nominal state (OK or UP).

See also: Acknowledging an alert.


An alert is one of the following statuses: Warning, Down, Critical, Unknown.

The term alert is used in this way in the pre-defined filters on page Resources Status.

Central server​

In Centreon, the central server is the main console where you monitor resources. The central server allows you to:

  • configure the monitoring of your whole infrastructure,
  • monitor resources
  • see what all your Centreon servers (all pollers) monitor, using its web interface.


Downtime is a period during which notifications are disabled for a resource. Downtime is used during planned maintenance operations, to avoid unnecessary alerts.

See also: Planning a downtime.


See Monitoring engine.


Fully Qualified Domain Name: hostname and domain name for a server. Example: (hostname: demo, domain name:


Graphs are generated from the metrics that make up services. They show how these metrics evolve over time.

See also: Charts management and the other topics in this section.


Principle according to which a parameter of a template is applied to the resource that inherits from this template.


Equipment that has an IP address or an FQDN, and that you want to monitor. Examples: a Linux server, an internet router, a website, a 3D printer, an EC2 instance, a docker host, a cash register, etc. A host can have one or more associated services.

A host can have one of the following statuses: OK, DOWN and UNREACHABLE.

See also: Monitoring a host and the other topics in this section.


A metric (or performance data) is part of a service. This piece of data allows you to display graphs and to define thresholds according to which you will receive notifications. These thresholds will determine the status of the service the metric belongs to.

When a service has several metrics, the status of the service is the status of the worst metric.

You can see all metrics attached to a service in the details panel of the service.


Modes are used in plugins. In most cases, a mode corresponds to a service template. The mode appears in the execution command for the connector. In the Centreon interface, you don't need to specify a mode explicitly: its use is implied when you apply a service template. However, you will need to specify the correct mode for the template if you want to test the execution command for the connector in your terminal, or to create a custom command.

The documentation of the Monitoring Connectors provides a list of available modes for each connector, with all the corresponding options.

Monitoring action​

Any action performed in the interface that acts on your monitoring in real time. For instance, to acknowledge a resource, to plan a downtime, to force a check, etc.

Monitoring Connector​

The term "Monitoring Connector" refers to a plugin and the corresponding pack.

A pack contains the configuration of the plugin in Centreon (command, templates, thresholds), as well as data required by the automatic discovery feature.

See also:

Monitoring engine​

Centreon Engine is the software component that plans checks, executes them, and notifies users if an incident occurs. Centreon Engine is present on pollers and the central server.


Message that warns a user that an incident has occurred.

Performance data​

See Metric.


A plugin is a monitoring probe, i.e. a binary executable or a script that is called by the monitoring engine to carry out a check on a host or service. The plugin determines which status should be sent to the monitoring engine, based on the checks it makes and on the thresholds defined in the configuration of the host or service.


A poller is a monitoring server installed in your infrastructure to monitor your resources. A poller is attached to the central server.

  • A Centreon poller monitors resources. It has a monitoring engine.

  • A poller has no graphical interface: the resources it monitors are displayed in the interface of the central server it is attached to.

"Poller" is also used to refer to the monitoring engine that is present in a central server and a poller.

Recurring downtime​

Recurring downtime periods are downtimes that occur regularly.

See also: Recurrent downtimes.


Object monitored by a Centreon platform (hosts, services, metaservices).


See Monitoring engine.


A service is attached to a host. It is a check point on this host, that can relate to:

  • the status of a component: is the power supply connected? Is my instance started?

  • the performance of a component: is my website accessible in less than 0.5 s? What are the ink levels on my printer? How much of the memory is used on my server?

A service can consist of one or several metrics.

A service can have one of the following statuses: OK, WARNING, CRITICAL, UNKNOWN.

See also: Monitoring a service and the other topics in this section.


Unhandled, acknowledged, in downtime.



  • the availability of a host (UP, DOWN),

  • the availability or performance of a service (OK, WARNING, CRITICAL, UNKNOWN).

PENDING is not a status: a resource is "pending" when it has just been created and hasn't been checked yet.

See also: Possible statuses of a resource.

Status type​

Indicates whether a change in status is confirmed (HARD) or not confirmed (SOFT). For instance, if a status becomes HARD, notifications are triggered.

See also: Status types.


Skeleton of a resource that is preconfigured so that parameters defined on the skeleton are applied to the resource that inherits from it.

There are host templates and service templates.

See also:


Configurable visual element that allows you to display data in a custom view.

See also: Custom views.