@Override
    public void unHealth(Throwable t) {
        log.error("Health check fails", t);
        metrics.setValue(1);
    }
HealthCheckMetrics intends to record health status.
oap-server/server-telemetry/telemetry-api/src/main/java/org/apache/skywalking/oap/server/telemetry/api/HealthCheckMetrics.java