Naemon vs OpenNMS Horizon
A side-by-side comparison of two self-hosted monitoring & status options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | Naemon | OpenNMS Horizon |
|---|---|---|
| Deploy effort | Read-the-docs project | Under-an-hour setup |
| Health score | 73 · Good | 83 · Excellent |
| Category | Monitoring & Status | Monitoring & Status |
| License | GPL-2.0 | AGPL-3.0 |
| Language | C | Java |
| Setup difficulty | Hard | Hard |
| Min. RAM | 256 MB | 4,096 MB |
| Deployment | bare-metal, source | docker, bare-metal |
| GitHub stars | ★ 173 | ★ 1,173 |
| First released | 2014 | 2000 |
| Replaces | SolarWinds, PRTG | SolarWinds, PRTG |
What are Naemon and OpenNMS Horizon?
Naemon
Naemon is a host and service monitoring tool based on the Nagios core, designed for improved performance and modern features. It checks the availability of resources and alerts on outages.
- Nagios-compatible checks
- Improved performance
- Livestatus query interface
- Large plugin compatibility
OpenNMS Horizon
OpenNMS Horizon is an enterprise-grade network monitoring and management platform that handles fault, performance, and traffic monitoring at scale. It supports SNMP, flow analysis, and event correlation.
- Fault and performance monitoring
- Flow analysis
- Event correlation
- Scales to large networks
Naemon vs OpenNMS Horizon: key differences
Naemon is written in C, while OpenNMS Horizon is built with Java. Licensing differs — GPL-2.0 for Naemon versus AGPL-3.0 for OpenNMS Horizon. Naemon is the lighter option, starting around 256 MB of RAM against 4,096 MB for OpenNMS Horizon. OpenNMS Horizon is the more established project (first released 2000), while Naemon arrived in 2014. OpenNMS Horizon has the considerably larger community, at 1,173 GitHub stars versus 173. OpenNMS Horizon lists first-class Docker deployment; Naemon does not.
Why pick each one
Choose Naemon if…
- Faster than classic Nagios
- Reuses Nagios plugins
Watch out for
- Text-file configuration
- Needs add-ons for a modern UI
Choose OpenNMS Horizon if…
- Released under the AGPL-3.0 license
- First-class Docker support for quick deployment
- Active community (1.2k GitHub stars)
- Written in Java
Frequently asked questions
Is Naemon or OpenNMS Horizon better?
Neither is universally better. OpenNMS Horizon has the larger community; both share a hard setup difficulty, so the decision comes down to features and licensing.
Are Naemon and OpenNMS Horizon free and open-source?
Yes. Naemon is licensed under GPL-2.0 and OpenNMS Horizon under AGPL-3.0. Both can be self-hosted at no software cost.
Can I run Naemon and OpenNMS Horizon with Docker?
Naemon: check the project docs for container support. OpenNMS Horizon: yes.
Which is lighter on resources, Naemon or OpenNMS Horizon?
Naemon has the smaller minimum footprint at 256 MB of RAM, compared to about 4,096 MB for OpenNMS Horizon. Real-world usage depends on library size, user count, and enabled features.