Health check

A health check (health_check) is an optional probe spec on a device-bound connector. The gateway periodically reads a resource and discards the reading — a probe never produces telemetry or device shadow data.

• Fields: resource, interval_ms (default 30000), timeout_ms (default 5000, must be shorter than the interval), and fail_threshold (default 3).
• The gateway owns the online/offline edge: it marks reachability from consecutive probe results.

Health checks are only meaningful when the connector is bound to a sub-device; a gateway-level connector has no single resource owner to probe.