Corrects the #459 finding. 2-node keep-oldest recovery works fine (the ScadaBridge
sister project proves it); OtOpcUa was missing the supervision pieces that make it
automatic, and docs/Redundancy.md wrongly claimed in-place oldest-crash failover.
Mechanism (confirmed on a 2-container rig + by decompiling Akka KeepOldest.OldestDecision):
on an OLDEST-node crash keep-oldest downs the LONE survivor (DownReachable including
myself) — down-if-alone can't rescue a lone survivor (its branch needs >=2 survivors).
Recovery is exit-and-rejoin: run-coordinated-shutdown-when-down terminates the node and
the service supervisor restarts it. My earlier 'total outage' was a docker-dev artifact
(no restart policy); production Install-Services.ps1 already has sc.exe failure restart.
Changes (ScadaBridge parity):
- ActorSystemTerminationWatchdog (Host, registered after AddAkka): watches
ActorSystem.WhenTerminated and on an unexpected self-down calls StopApplication so the
process exits (supervisor restarts it) instead of idling with a dead actor system.
Distinguishes graceful shutdown via _stopRequested + ApplicationStopping. 3 unit tests.
- docker-dev: restart: unless-stopped on the host anchor (models production supervision) +
both redundancy peers in SeedNodes so a restarted node re-forms via either peer.
- docs/Redundancy.md: rewrote the split-brain recovery section — younger-loss = in-place
fast failover; oldest-loss = exit-and-rejoin under supervision (not in-place); the three
requirements (supervisor + watchdog + both-node seeds); flagged HardKillFailoverTests as
non-representative (Transport.Shutdown, not a real crash). Instant in-place takeover on
ANY single loss needs 3+ members.
Cluster.Tests 29/29 (SBR guards), watchdog tests 3/3, full solution builds.
Live re-verify of the watchdog image pending (host docker disk full).
Four continuous-historization types (IHistorizationOutbox, HistorizationOutboxEntry,
IHistorianValueWriter/HistorizationValue, HistorizationCommitMode) drifted into a
ZB.MOM.WW.OtOpcUa.Core.Abstractions.Historian sub-namespace while the other six files
in the same folder correctly use the root namespace. This violated decision #59's
flat-public-surface rule and left InterfaceIndependenceTests.AllPublicTypes_LiveInRootNamespace
red on master (pre-existing, predates round-2 remediation).
Move all four to the root namespace and drop/retarget the now-redundant
'using ...Core.Abstractions.Historian;' in the ~11 consumers. No behavioral change.
Verified: Core.Abstractions.Tests 129/129 (was 128/129), Runtime.Tests Historian+DI 72/72,
Gateway driver unit 102/102, full solution build 0 errors.
Models gain an optional bool? Writable (absent stays omitted; explicit false round-trips,
unknown keys preserved); the six editors gain a Writable checkbox (FOCAS disabled+read-only
hint). 9 model round-trip tests green. docker-dev /run verify of one editor deferred-live.
Findings 01/S-1 (AddressSpaceApplyOutcome failure field + apply.failed logging,
no optimistic success), 06/S-1 (Galaxy write fails closed -> BadCommunicationError
+ #5 revert, no knowingly-lost raw Write), 03/S4 (PrimaryGatePolicy default-deny
unknown-role-multi-driver on all gates + scripted-alarm emit gate). T13/T15 (2-node
live gates) deferred -- T15 is the behavior-affecting S4 live gate, must run in heavy
pass. Clean merge, build clean.
Deletes the composer's ExtractTagFullName/Alarm/Historize/Array statics and (co-located
to keep the build green, per plan T5) the three OpcUaServer.Tests ExtractTag* suites whose
tables now live in Commons.Tests/TagConfigIntentTests. T10 is the grep-sweep verification.
Joseph Doherty