Module outlier 

Passive health checks via outlier detection.

Tracks error rates on live traffic and automatically ejects unhealthy backends. Unlike the circuit breaker (which uses failure rate over a sliding window), outlier detection triggers on consecutive errors, catching hard-down backends faster. Cross-backend coordination via max_ejection_percent prevents ejecting all backends simultaneously.

Configuration

[[backends]]
name = "flaky-api"
transport = "http"
url = "http://localhost:8080"

[backends.outlier_detection]
consecutive_errors = 5       # eject after 5 consecutive errors
interval_seconds = 10        # evaluation interval
base_ejection_seconds = 30   # how long to eject
max_ejection_percent = 50    # never eject more than half of backends

Structs

OutlierDetectionLayer

A Tower Layer that applies outlier detection to a backend.

OutlierDetectionService

Per-backend outlier detection middleware.

OutlierDetector

Shared state tracking ejection status across all backends.