Extends TwoNodeClusterHarness with three lifecycle primitives:
- StopNodeBAsync() — graceful CoordinatedShutdown (Cluster.Leave)
- RestartNodeBAsync() — rebuild node B on same Akka port + same in-memory DB
- WaitForClusterSizeAsync(n) — converge assertion helper
Adds three failover scenario tests:
- Stopping node B shrinks cluster to 1 Up member
- Restarted node B rejoins on the same Akka port
- Deployment started with B down seals with a single NodeDeploymentState
(validates ConfigPublishCoordinator.DiscoverDriverNodes snapshots
membership at dispatch time)
Closes follow-up F22. Integration test count: 6 → 9 (+3).
- New Commons.Messages.Fleet.GetDiagnostics request record.
- DriverHostActor handles GetDiagnostics in all three states (Steady, Applying,
Stale); replies with a NodeDiagnosticsSnapshot built from _currentRevision
+ the local NodeId. Drivers list is empty until F7 wires the per-instance
children.
- FleetDiagnosticsClient now resolves the target via ActorSelection at
akka.tcp://{system}@{nodeId}/user/driver-host and Asks with a 3s timeout.
On timeout/peer-down it returns an empty snapshot so the UI degrades
gracefully rather than throwing.
Two new integration tests in Host.IntegrationTests:
- GetDiagnostics_returns_snapshot_with_target_NodeId verifies the
cross-node Ask/Reply works.
- GetDiagnostics_after_deploy_reports_current_revision exercises the
end-to-end path: AdminOps starts a deployment, both DriverHostActors
apply, then diagnostics reports the new revision on both nodes.
All 98 v2 tests pass (was 96 + 2 new).
DeployHappyPathTests exercises the full deploy pipeline on the 2-node harness:
AdminOperationsActor → ConfigPublishCoordinator → DistributedPubSub →
DriverHostActor on both nodes → ApplyAck → coordinator seals. Verifies both
NodeDeploymentState rows reach Applied and Deployment.Status reaches Sealed.
Exposed + fixed two production bugs along the way:
1. Coordinator was publishing DispatchDeployment on the "deployments" topic but
never subscribed to anything — DriverHostActor ACKs published on the same
topic could not reach it. Added dedicated "deployment-acks" topic with
coordinator subscription in PreStart, and DriverHostActor publishes ACKs
there.
2. NodeId derivation used member.Address.Host only — two cluster members on a
shared loopback host (test harness, dev VMs) collided to one identity. The
coordinator's expected-ack set became {1} and the system sealed after only
half the nodes acked. Switched to host:port everywhere (ClusterRoleInfo +
coordinator) so loopback nodes stay distinct and production identities are
harmlessly more specific.
Tests: 95 v2 tests pass (was 93 + 2 deploy tests), 0 skipped.
Failover scenarios (design §8 cases 3-7: node-kill-mid-apply, split-brain,
restart-during-deploy) deferred — they need controlled node-down primitives
on the harness. Tracked as F22 (failover scenario test cases).
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.
