SNMP.
The old engine was nagios. The new engine will be telegraf -> mqtt -> brokerfest -> timescale -> Prometheus.
I guess. Not sure yet. The brokerfest is a series of broker pubsub between sites to both split out data from the stream for off-site CC, or pull its own subscriptions in. Data could go host <- telegraf -> broker -> remote broker -> remote timescale -> remote Prometheus