Health check.
also: health checks · health checkingA periodic probe (often GET /health) a load balancer uses to detect unhealthy servers and stop sending them traffic.
the two-minute refresher
- The balancer calls an endpoint on an interval, for example every 30 s with a 5 s timeout.
- A server is marked unhealthy after N consecutive failures and healthy again after M successes.
- Thresholds avoid flapping: one slow response should not eject a server.
- Check what matters: a /health that only returns 200 can hide a dead database connection.