OpenNMS HORIZON is packaged with an internal repository of plugins which are can be installed in Karaf and activated by a user using the Plugin Manager in the same way it could be used to download external plugins. The internal-plugin-descriptor feature maintains a list of internal plugins which are packaged with OpenNMS HORIZON.
The list of internal plugins can be accessed by setting the Available Plugins Server Plugin Server URL to the address of the local OpenNMS HORIZON (i.e. http:\\localhost:8980\opennms) and clicking 'reload available plugins'. The available internal plugins will then be added to the Available Plugins Tab and can be installed and started by the user as described previously. (You should use the OpenNMS HORIZON rest or admin username and password to access the local available plugins).
Example internal plugins included with OpenNMS HORIZON are the Alarm Change Notifier and the Elasticsearch ReST Interface.