OpenNMS is an open source enterprise network monitoring platform for complex, distributed infrastructure. It covers monitoring, traffic analysis and alerting, and relies on an event-driven architecture that can be extended for service polling and data collection, with a distributed and tiered design aimed at large environments. It is published under the AGPLv3 licence. Meridian is the commercial subscription version, offered as an optimised and stable build, and The OpenNMS Group also provides commercial support, professional services and training.
The OpenNMS Group was founded in 2004 and describes itself as a subsidiary of NantHealth, a US company. It states that its headquarters are near Research Triangle, North Carolina, and its website lists a contact address in Lewisville, Texas. A US-headquartered supplier with a US parent may be subject to US jurisdiction, including the CLOUD Act, for the support and subscription relationship. The software itself is open source and is installed and run on your own infrastructure, so monitoring data stays where you deploy it, and the licence allows independent operation without the vendor.