The split-brain-resolver HOCON block in akka.conf was inert — nothing
registered a downing provider, so the cluster ran Akka's default NoDowning:
a hard-crashed node was never downed, cluster singletons + the driver
role-leader never failed over, and a partition left both redundancy sides
at ServiceLevel 240 indefinitely.
Activate the resolver via the typed ClusterOptions.SplitBrainResolver
(KeepOldestOption { DownIfAlone = true }) in a new testable
BuildClusterOptions helper. keep-oldest + down-if-alone is correct for a
2-node warm-redundancy pair. HOCON keeps stable-after (typed option can't
express it) + a cross-reference comment. Deterministic unit guard added;
end-to-end verified the resolved ActorSystem config carries the provider
and stable-after survives the HOCON/Hosting merge. Redundancy.md corrected.
Hard-kill failover integration test tracked as a follow-up (effort-M harness).
Adds <summary>/<param>/<returns>/<inheritdoc> where missing and removes
project bookkeeping IDs (task/tracking refs) from shipped code comments,
so the docs read cleanly and CommentChecker is quiet except for known
false positives (PLC/protocol terms, event/IEqualityComparer inheritdoc).
Doc/comment-only; no logic changed; solution builds clean.
DriverHostActor/DriverInstanceActor and cluster events log via Akka's ILoggingAdapter, which had no Serilog bridge — under the Windows service host the default StandardOutLogger output is discarded, making the driver-role actor graph invisible (this masked the data-plane diagnosis).
- Add Akka.Logger.Serilog 1.5.60 (deps satisfied by Akka 1.5.62 / Serilog 4.3.1).
- WithOtOpcUaClusterBootstrap: ConfigureLoggers(DebugLevel; ClearLoggers(); AddLogger<SerilogLogger>()) — Akka.Hosting owns logger setup, so HOCON akka.loggers alone is not honored.
- Program.cs: set static Serilog.Log.Logger from the DI root logger after Build() (AddZbSerilog registers the MEL provider but not the static logger, which the Akka SerilogLogger and the startup banner both need).
Adds <summary>, <param>, <typeparam>, and <inheritdoc/> tags to public
members surfaced by commentchecker — resolves 5,847 of 5,869 issues
(99.6%) across three /fixdocs passes.
Builds TwoNodeClusterHarness: two in-process Host-equivalent nodes sharing
an in-memory ConfigDb. Forms a 2-member Akka cluster. ClusterFormationTests
proves both nodes see each other as admin+driver role members.
Fixes a real production bug uncovered while wiring the harness — Program.cs
ran two separate ActorSystems (one from AddOtOpcUaCluster.AkkaHostedService
with cluster HOCON, one from Akka.Hosting.AddAkka with bare HOCON). Cluster
singletons landed on the bare ActorSystem and could not actually form a
cluster ("Configuration does not contain `akka.cluster` node").
Consolidation:
- AddOtOpcUaCluster now only binds AkkaClusterOptions + registers IClusterRoleInfo
- New WithOtOpcUaClusterBootstrap pushes embedded HOCON + Remote/Cluster options
into Akka.Hosting's AkkaConfigurationBuilder
- AkkaHostedService.cs deleted — Akka.Hosting now owns the lifecycle
- Program.cs + harness call WithOtOpcUaClusterBootstrap inside AddAkka
Why not WebApplicationFactory<Program>? Program.cs reads OTOPCUA_ROLES from
process env (shared across in-process WAFs); the harness replays Program.cs's
DI graph from a clean WebApplicationBuilder per node with per-node config
overrides. Same production extensions, isolated config + Kestrel + Akka ports.
Tests: 93 v2 tests pass (was 91 + 2 new cluster formation), 0 skipped.
Joseph Doherty