A node frozen past failure detection + StableAfter, or both sides of a partition
that heals after each downed the other, used to stay a second active node until an
operator restarted one: the peer quarantines the removed UID and Akka.Cluster
1.5.62 never acts on ThisActorSystemQuarantinedEvent.
ShutOutRestart (child of the LeaderAutoDown downing actor; opt-out via
ScadaBridge:Cluster:LeaderAutoDown:RestartWhenShutOut, default on for
leader-auto-down only) watches two signals:
- S1 ThisActorSystemQuarantinedEvent: the peer quarantined this node. If the peer
is still a live member here, only this side can be shut out -> restart now.
- S2 AssociationErrorEvent 'has a UID that has been quarantined': the peer still
runs the incarnation this node removed. A healed partition yields only S2, on
both sides. Wait ShutOutGrace (60s) for a frozen peer to restart itself, then
tiebreak.
Tiebreak: the higher address (Akka Member.AddressOrdering) restarts, the lower
stays and restarts only if still split one grace later. Removed peers are probed
(Identify, 5s -> 60s back-off) since nothing else contacts them after mutual
removal. Restart = Cluster.Down(self) -> existing self-down path.
The Host now exits 75 after an unplanned ActorSystem termination (and sets it on
the Windows service before it reports stopped): SCM recovery with failureflag 1
only restarts a service that stops with a non-zero code, and the watchdog used
to exit 0. Shipped default strategy stays auto-down.
Claude-Session: https://claude.ai/code/session_01GT67ACmpMR7b9LGRPLijMi
Joseph Doherty