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Network & SecurityLoad Balancer

Health checks

The load balancer actively probes every backend on a fixed interval. A backend that fails enough consecutive probes is removed from rotation; it returns automatically once it passes again. Health checks are configured under Active health check in the Routing and health section of the create form, and cannot be changed after creation.

Check types

TypeWhat it verifies
http (default)The backend returns a successful response for a GET on the configured Path
httpsSame as http, over TLS
tcpA TCP connection can be established on the backend port — no path involved

Use http/https whenever your service exposes a health endpoint — a TCP check only proves the port is open, not that the application can serve requests.

Settings

FieldDefaultDescription
Path/healthRequest path for http/https checks
Interval10000 msTime between probes
Timeout2000 msHow long a probe waits before counting as a failure
Healthy threshold2Consecutive passes before a backend re-enters rotation
Unhealthy threshold3Consecutive failures before a backend is removed

With the defaults, a failing backend is removed after roughly 30 seconds (3 failures × 10 s interval) and restored about 20 seconds after it recovers.

Choosing a health endpoint

  • Return 200 only when the service can actually do work (dependencies reachable, not just process-up).
  • Keep the endpoint fast and unauthenticated — it’s probed every few seconds.
  • Don’t reuse a heavy endpoint; a dedicated /health route avoids cache and auth side effects.