What’s New in OpenNMS Meridian 2022

System Requirements

  • Java 11: OpenNMS Meridian 2022 runs on JDK 11.

  • PostgreSQL 10 or higher: Meridian 2022 requires any supported version of PostgreSQL from 10 up to (and including) 14.

Breaking Changes

Running as Non-Root

By default, OpenNMS now runs as the opennms user rather than root.

If you are upgrading from a version of OpenNMS Meridian older than 2022, you will have to fix the ownership of your files.

Fixing Permissions and Ownership

Since many OpenNMS instances are very large with thousands or even millions of RRD and similar data files in $OPENNMS_HOME/share, we decided not to change ownership automatically upon package upgrade.

The OpenNMS installer will detect if you need to fix the ownership of your files and warn you to run the script to fix permissions ($OPENNMS_HOME/bin/fix-permissions) in this case.

If you wish to revert to the previous behavior, create an $OPENNMS_HOME/etc/opennms.conf file if it doesn’t already exist, and set RUNAS.


Change the user to root in the systemd unit by editing the systemd unit file.

systemctl edit opennms
Add the following content

Save the file and reload systemd with systemctl daemon-reload and restart OpenNMS with systemctl restart opennms. The OpenNMS process should run as root user instead of opennms and can be verified with ps -aux | grep java.

Trapd Port Changes

As OpenNMS can no longer listen on privileged ports by default, the default Trapd port is now 10162. You will need to configure a proxy agent or port forward to continue to receive traps at port 162. Otherwise, you must configure your agents to send traps to the new port instead.

Java ICMP Permissions

OpenNMS will attempt to configure ICMP permissions using the net.ipv4.ping_group_range sysctl. However, Linux kernels older than version 3.11 (like the version provided by CentOS 7) do not support this setting fully.

If you are on a distribution with an older unsupported kernel, you can give Java ICMP permissions using the setcap utility once you have completed your upgrade. Note that this example assumes you have already run $OPENNMS_HOME/bin/install after install or upgrade, so $OPENNMS_HOME/etc/java.conf exists.

setcap cap_net_raw+ep $(</opt/opennms/etc/java.conf) && echo "$(dirname $(</opt/opennms/etc/java.conf))/../lib/jli/" > /etc/ld.so.conf.d/java.conf && ldconfig -v

Kafka RPC Single Topic

This release changes the Kafka RPC default configuration to publish on a single target. If you are using Minions, both the Minion and OpenNMS need to be updated.

Make sure that Kafka lag on Sink topics is minimal before upgrading, or there may be loss of those sink messages.

Also, the Twin API has replaced the OpenNMS REST API for synchronizing Trapd configuration updates. Additional settings are needed on both Minion and Meridian to enable Twin when not using the ActiveMQ message broker.

Refer to the deployment section in the documentation for details.

In Meridian 2022, we consolidated IPC features on Minion. This groups all IPC (Sink/RPC/Twin) features of JMS into one feature as openms-core-ipc-jms. Similarly for Kafka and gRPC. When using Kafka or gRPC, you need to disable opennms-core-ipc-jms instead of disabling individual features such as opennms-core-ipc-sink-camel.

Situation Feedback Persistence Configuration

The configuration file etc/org.opennms.features.situation-feedback.persistence.elastic.cfg has been renamed to etc/org.opennms.features.situationfeedback.persistence.elastic.cfg (i.e. the minus sign is removed from the filename). This fixes a race condition on startup when using ALEC.

SQS Minion IPC Support Dropped

Support for Amazon SQS for Minion communication has been removed. We recommend to use Kafka instead for use cases that require horizontal scaling of Minion communication.

Time Series Integration Layer Changes

The Time Series integration layer has gone through a number of big improvements to reduce the complexity and cardinality of metadata and tags.

  • Time series plugins need to be compatible with OIA 0.6.x.

  • Resource-level string attributes are now also stored via the plugin in the respective time series database. The timeseries_meta table which previously stored this metadata has been removed. There is no migration; string values are generally updated on the next poll.

New Features and Improvements

Flows and streaming analytics

Streaming analytics and flow processing have gone through a number of major enhancements.

  • A huge number of perfomance improvements have been made since Meridian 2021.

  • Flow aggregation now supports DSCP ToS/QoS fields.

  • Flow metadata has been tuned and redundancy has been removed, resulting in less data being stored per update.

  • Elasticsearch persistence has been improved to support batching updates.

  • The flow classification engine has been almost entirely rewritten to be considerably more performant when processing large rulesets.

  • Support has been added for persisting flows to Cortex.


The Minion continues to receive improvements in performance and features, most notably the addition of a new API (the "Twin API"), which pushes configuration to Minion over RPC, reducing the amount of data that needs to be passed over the wire.

The first subsystem to adopt this new API is SNMPv3 auth data, so the Minion no longer needs to make a REST call to the OpenNMS core. Over time, all configuration information will be migrated to this new API.


  • The Minion confd file has been updated with a bunch of documentation describing various options.

  • Support has been added for exporting a number of JMX metrics through Prometheus for out-of-band monitoring of the Minion.

  • The Minion now has support for querying its health through REST.

Polling and Metadata


GeoIP Provisioning Adapter

You can use the GeoIP Provisioning Adapter to enrich a node’s asset data with location information. It uses the GeoIP2 Databases from MaxMind to look up longitude/latitude values for a given IP address.


  • Initial support for enumerating REST API endpoints has been added, using Swagger. A link is available in the "help" section of the web UI.

  • Elastic flow queries return additional data for DSCP QoS/ToS data.

  • RTC data now includes an additional boolean field for service up/down status.


  • A ton of work has gone into cleaning up, rearranging, and standardizing terms in the documentation.

  • A bunch of additional REST APIs are now documented through OpenAPI.

Important Internal Changes

  • Kafka components have been updated to version 2.8.0

  • Our embedded Karaf has been updated to version 4.3.2

Other Improvements

Since Meridian 2022 is based on Horizon 29, it contains all the fixes and updates that have occurred since Meridian 2021 was created from the Horizon 27.1 codebase.

For a more complete list of major changes included in this release, see the "What’s New" documentation: