Native OpenNMS support.
Current support is through NRPE. This may require a fork and a separate project, but it might not. It may also be that NRPE could still be used, but the output could be improved for OpenNMS. Ultimately, this is early days, as we have not begun testing on OpenNMS. Please feel free to add jobs for additional monitoring tools, and we can look into it.
"OpenNMS's NRPE support is...not used or maintained, and may not be reliable."
So...