What is Flapping?

Flapping is a monitor or alert that switches rapidly between OK and failing, typically because the target is on the edge of a timeout or a threshold. Each flip can produce an alert and a resolution, which floods the channel and trains people to ignore it.

Defences include a failure threshold of several consecutive checks before alerting, a resolve delay before clearing, longer timeouts for slow but healthy targets, and grouping in the alert router. Alertmanager handles the same problem on the routing side with group_wait and group_interval.