Troubleshooting Minion connectivity and functions

The Horizon and Meridian Minion come with a few useful built-in commands to verify configurations and debug access to Management Agents.

Testing Connectivity

Once the URLs and credentials for communicating with the Horizon/Meridian Core server are configured, you can verify connectivity.

Connect to the Minions Karaf Shell

ssh -p 8201 admin@minion-host-ip

Run the health check command


Depending on your configuration you should see the following output

Verifying the health of the container

Connecting to OpenNMS ReST API                                                                      [ Success  ]
Verifying installed bundles                                                                         [ Success  ]
Connecting to JMS Broker                                                                            [ Success  ]
Verifying Listener Single-Port-Flow-Listener (org.opennms.netmgt.telemetry.listeners.UdpListener)   [ Success  ]

=> Everything is awesome

The health check tests

  • Installed Karaf bundles and features can be started
  • Connecting to the message broker, either ActiveMQ, Kafka or gRPC
  • Connecting to the REST endpoint of the Core server
  • Test Flow listener configurations

If you have issues you have to check the data/log/karaf.log file in your Minion install directory or run the command log:tail in the Karaf shell.

Execute SNMP commands through a Minion

This section describes how to run SNMP commands from the Core Server to a device behind a Minion in a remote network. It is equivalent as executing the snmpwalk command from the Minion to your SNMP agent on your device.

Connect to the Minions Karaf Shell

ssh -p 8201 admin@minion-host-ip

Execute an SNMP walk against a device in the remote location

snmp:walk -l MyLocation IpAddressInMyLocation

This command helps you to verify a) if the SNMP community configuration for a given host in a remote location is correct, b) the Minion can reach the device in his remote location and c) if RPC calls can be executed from the Core Server to the Minion.

Run a monitor through a Minion

You can run an adhoc test for every monitor from the Karaf CLI. This gives you an example how to ping a device in a remote location through a Minion.

List available monitors you can run for a test


Run an ICMP monitor through a Minion

opennms:poll -l MyLocation -t Time-To-Live-in-ms org.opennms.netmgt.poller.monitors.IcmpMonitor myIpAddress

The Time To Live (TTL) is only related to messages in the ActiveMQ communication.

In case a poll is triggered manually through Karaf CLI the message ZTL in ActiveMQ should be at least the number of retries x timeout in ms, e.g. 3 x 2000ms = 6000ms.

By default, the configured polling interval is used, which is by default 5 minutes (300000 ms).

Further Readings

You can find more useful Karaf commands in our Karaf CLI Cheat sheet.

:woman_facepalming: You can fix me, I’m a wiki post.