The controller no longer subscribes to the alive message: HostBeats, its handler, the heartbeat-gap duration and a fixed silent bound (issue 1183, AC3, AC4, AC5)

cmd/mesh-controller/signals.go

@@ -318,6 +318,10 @@ func ago(d time.Duration) string {
 	return d.Round(time.Minute).String()
 }
 
+// silentBound is how long a machine may go unheard, where the watchman gives no verdict: three of the intervals nodes have
+// always used, fixed now that no machine says its own (issue 1183).
+const silentBound = heartbeatsMissed * heartbeatEvery
+
 // heartbeatBound is a machine's S1 or S11 bound from the interval it says.
 func heartbeatBound(every time.Duration) time.Duration {
 	if every <= 0 {
@@ -333,7 +337,7 @@ func watchHeartbeats(f *signalFacts) []conditions.Observation {
 			// Never heard is a machine that has not joined, which status says; asleep is not lost.
 			continue
 		}
-		bound := heartbeatBound(m.every)
+		bound := silentBound
 		silent := f.now.Sub(m.lastHeard)
 		if !m.silent(f.now) {
 			continue