IOpcUaEndpointState (review-remediation lane C3) recorded whether the SDK started, but only the
health check read it: a fused node whose endpoint failed (port 4840 taken, ...) still advertised
250/240 and stayed driver Primary, so the Primary-gated data plane ran on a node no client could
reach while the reachable peer refused writes as Secondary.
- Move IOpcUaEndpointState/OpcUaEndpointState/OpcUaEndpointStatus from Host to Commons.OpcUa so
the Runtime can consume it.
- ServiceLevelCalculator: new NodeHealthInputs.EndpointListening (default true). false -> 0,
ahead of every other input including the +10 Primary bonus.
- OpcUaPublishActor: takes the endpoint state, feeds EndpointListening (Failed only; NotStarted /
Stopped are boot/shutdown windows) on the DB-backed and DB-less paths, and the legacy role-only
seam returns 0 for a failed endpoint too.
- New OpcUaEndpointStepDownActor (one per driver node): a Primary (ClusterActiveNode.SelfIsActive,
the election's own primitive) with a Failed endpoint gracefully Leaves its mesh - the manual
failover mechanism - so the peer becomes the oldest Up driver member, hosts the singletons and is
Primary. The election itself is not bent. Guarded on a peer having recently reported its own
endpoint listening (EndpointReport on the new opcua-endpoint-state DPS topic), so a pair with
both endpoints failed does not bounce the role and restart nodes forever, and a lone node never
shuts itself down.
- Runtime now references ZB.MOM.WW.Health.Akka (ClusterActiveNode).
- Docs: Redundancy.md tier table + new "Endpoint start failure: Primary step-down" section;
cluster-topology rule; HealthEndpoints / OpcUaEndpointHealthCheck comments (F-C1 landed).
Tests: ServiceLevelCalculatorTests (+5), OpcUaPublishActorEndpointStateTests (7: DB-less,
DB-backed, legacy seam, NotStarted/Stopped do not demote, a later failure demotes on the next
tick), OpcUaEndpointStepDownActorTests (3, real two-node mesh: holds while the peer is not
listening then leaves and the peer becomes Primary; failed Secondary and healthy Primary never
leave). Each was mutation-checked: removing the calculator/legacy guard, the Leave, the
peer-listening guard or the Primary guard fails the corresponding tests.
Joseph Doherty