General OpenNMS frequently asked questions
What is OpenNMS?
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What can OpenNMS monitor?
Almost anything. There are a lot of built-in definitions to monitor and/or collect performance metrics on a variety of systems. If your device is not on this list, there may be some community-contributed configurations available—or you can easily create your own. ICMP/Ping DNS DHCP HTTP(S) FTP JDBC SNMP [...]
What’s the difference between Horizon and Meridian?
OpenNMS Meridian and Horizon are both fully open source and licensed under the AGPLv3. What's the difference? Meridian is an optimized, stable version of OpenNMS, via a subscription, that maximizes the platform’s value and minimizes the effort required to maintain it. Meridian is curated by The OpenNMS Group for production [...]
What are the requirements for a basic OpenNMS installation?
For a single-server proof-of-concept with up to 100 "average" nodes, a good starting point might be: Red Hat Enterprise Linux 8 or CentOS 8 (simplifies dependencies versus Red Hat Enterprise Linux 7) 4 CPU cores 4GB physical memory 100GB disk, preferably SSD We define a node as any device or [...]
What’s the base operating system required to install OpenNMS?
OpenNMS Meridian requires one of the following operating systems. See the latest Meridian release notes for information about OS support changes.Operating System Compatible Versions (64-bit):Red Hat Enterprise Linux 7.x & 8.xCentOS 7.xCentOS Stream 9.xOpenNMS Horizon requires one of the following operating systems. See the latest Horizon release notes for information [...]
What database(s) does OpenNMS use?
The core of OpenNMS uses PostgreSQL. It can be on the same server for smaller deployments, but we recommend using a separate cluster for better performance in larger networks. Depending on which features you configure, you may require other data stores. Our telemetry/flow collection service requires an Elasticsearch cluster. By [...]
What if I have multiple sites with devices to monitor?
Not a problem. Deploy OpenNMS in your primary site and then set up our Minion appliance component at remote sites. The core server will control the Minions to monitor nodes at that site and all collected data will be rolled up from the Minion to the core OpenNMS instance for a centralized view of your network. If you're collecting flow [...]
What other systems can OpenNMS integrate with?
In addition to a robust REST API that allows you to easily get data in and out of OpenNMS, we have a direct integration with many other systems and protocols (too many to list here). These include, but are not limited to: Notifications Email Slack Mattermost Custom scripts [...]
How many devices and number of alarms can be supported per instance?
An instance is each individual installation of Meridian or Horizon. While there is no built-in limit on either, the answer comes down to individual network environments versus a simple count of nodes and alarms. Scalability in an enterprise monitoring system rests on the amount of work required to monitor the inventory, which is measured in a more [...]
Is there artificial intelligence/machine learning (AI/ML) available for OpenNMS?
OpenNMS ALEC (Architecture for Learning Enabled Correlation) is our framework that uses artificial intelligence and machine learning to group related alarms so you can better manage the more complex situations they might represent. ALEC uses temporal clustering techniques, machine learning algorithms, and deep-learning technology with topology data to group related [...]
