Auto Discovery

Auto discovery is the process of automatically adding nodes to Horizon. You do this through discovery, either periodically on schedule or through single, unscheduled times.

Make sure you complete the tasks in the Getting Started section before adding nodes.

Configure discovery

Configuring discovery specifies the parameters Horizon uses when scanning for nodes.

  1. Click the gear icon and in the Provisioning area choose Configure Discovery.

    To configure a discovery scan to run once, select Run Single Discovery Scan.
  2. In the General Settings area, accept the default scheduling options (sleeptime, retries,timeout, etc.), or set your own.

  3. From the Foreign Source list, choose the requisition to which you want to add the discovered nodes.

  4. If you have installed Minions, select one from the Location list.

  5. Click Add New to add the following:

    • specific address (IP addresses to add)

    • URLs

    • IP address ranges to include

    • IP address ranges to exclude

  6. Click Save and Restart Discovery.

  7. When the discovery is finished, navigate to the requisition (Manage Provisioning Requisitions) where you specified to view the nodes discovered.

  8. If desired, edit the nodes or delete them from the requisition, then click Synchronize to add them to the Horizon database.

  9. Repeat this process for each requisition you want to provision.

Automatic discovery detectors

Auto discovery with detectors lets users specify the services to detect, in addition to ICMP ping, for the specified IP addresses to be discovered. Discovery sends a new suspect event only when the specified detectors succeed. A definition without any detectors will fall back to ICMP ping for discovery.

Sample discovery configuration with detectors:
<discovery-configuration xmlns="" packets-per-second="1"
    initial-sleep-time="30000" restart-sleep-time="86400000" retries="1" timeout="2000">

    <definition location="MINION" foreign-source="ApexOffice">

			<detector name="reverse-dns-lookup" class-name="org.opennms.netmgt.provision.detector.rdns.ReverseDNSLookupDetector"/>
			<detector name="SNMP" class-name="org.opennms.netmgt.provision.detector.snmp.SnmpDetector">
				<parameter key="timeout" value="5000"/>
				<parameter key="ttl" value="120000"/>







Manual discovery configuration

In addition to the configuration above, there are some optional settings you can configure via ${OPENNMS_HOME}/etc/discovery-configuration.xml.

Table 1. Discovery configuration parameters
Name Default Description



Number of ICMP packets that will be generated each second.


30000 ms (30 seconds)

The time, in milliseconds, before the discovery process begins after OpenNMS has started. This delay allows Horizon to fully start before generating new events.


86400000 ms (1 day)

Once the discovery process finishes, the time, in milliseconds, before it will start again.


2000 ms

The amount of time, in milliseconds, that the discovery process will wait for a response from a given IP address before deciding that there is nothing there.



The number of attempts to query a given IP address before deciding that there is nothing there.


not set

Adds discovered nodes to the specified foreign source requisition.



The monitoring location where this discovery batch will be executed. Only used when Minions have been deployed.



When using a monitoring locations and Minions, defines how many IP addresses are delegated to each Minion for scanning.

Table 2. Discovery range configuration parameters
Tag Description


Specify individual IP address(es) to discover. May be repeated multiple times.



Specify a range of IP addresses to discover. May be repeated multiple times.



Specify a range of IP address to exclude from discovery.

The exclude-range tag will override addresses only in an include-range. It will not override specific IP addresses or addresses included in a file. There is no "specific" version of the exclude tag. To exclude a specific IP address, use an exclude-range where the beginning and ending IP addresses are the same.


Specify the full path to a text file containing one IP address per line to include in discovery. You can embed comments in this file. Any content on a line after a # character is ignored.