Cacti 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 | Cacti | OpenNMS Horizon |
|---|---|---|
| Deploy effort | Under-an-hour setup | Under-an-hour setup |
| Health score | 85 · Excellent | 83 · Excellent |
| Category | Monitoring & Status | Monitoring & Status |
| License | GPL-2.0 | AGPL-3.0 |
| Language | PHP | Java |
| Setup difficulty | Medium | Hard |
| Min. RAM | 512 MB | 4,096 MB |
| Deployment | bare-metal, docker, source | docker, bare-metal |
| GitHub stars | ★ 1,871 | ★ 1,173 |
| First released | 2001 | 2000 |
| Replaces | PRTG, SolarWinds | SolarWinds, PRTG |
What are Cacti and OpenNMS Horizon?
Cacti
Cacti is a complete network graphing solution that harnesses RRDtool for data storage and graphing. It polls devices over SNMP and scripts, presenting historical performance data through a web interface.
- RRDtool-based graphing
- SNMP and script polling
- Plugin architecture
- Templating for devices
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
Cacti vs OpenNMS Horizon: key differences
Cacti is written in PHP, while OpenNMS Horizon is built with Java. Licensing differs — GPL-2.0 for Cacti versus AGPL-3.0 for OpenNMS Horizon. Cacti is the lighter option, starting around 512 MB of RAM against 4,096 MB for OpenNMS Horizon.
Why pick each one
Choose Cacti if…
- Mature and reliable
- Detailed graph templates
Watch out for
- Dated interface
- Configuration can be tedious
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 Cacti or OpenNMS Horizon better?
Cacti is the stronger all-round pick: it has both the larger community and the simpler medium setup. Consider OpenNMS Horizon if its specific feature set fits your needs better.
Are Cacti and OpenNMS Horizon free and open-source?
Yes. Cacti 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 Cacti and OpenNMS Horizon with Docker?
Cacti: yes. OpenNMS Horizon: yes.
Which is lighter on resources, Cacti or OpenNMS Horizon?
Cacti has the smaller minimum footprint at 512 MB of RAM, compared to about 4,096 MB for OpenNMS Horizon. Real-world usage depends on library size, user count, and enabled features.