ClusterClient→gRPC migration Phase 4 (docs/plans/2026-07-22-clusterclient-to-grpc-plan.md).
Phases 2/3 proved both directions on gRPC; this removes the Akka transport underneath.
Deleted:
- AkkaCentralTransport, AkkaSiteTransport (+ their dedicated tests)
- ISiteClientFactory + DefaultSiteClientFactory; CentralCommunicationActor legacy
ctor + SelectTransport (Host now builds GrpcSiteTransport and injects it)
- ClusterClient creation + both ClusterClientReceptionist.RegisterService calls in
AkkaHostedService; the RegisterCentralClient message + receive block
- CommunicationOptions.CentralContactPoints; the CentralTransport/SiteTransport
coexistence flags; the CentralTransportMode/SiteTransportKind enums
gRPC is now the only site↔central transport (site→central CentralControlService via
GrpcCentralTransport; central→site SiteCommandService via GrpcSiteTransport), both
built unconditionally by the Host. NoOpCentralTransport is the fail-loud null-default
so TestKit command-dispatch suites still construct the site actor without a wired
transport; production always injects GrpcCentralTransport.
Config: CentralGrpcEndpoints is now unconditional — CommunicationOptionsValidator
rejects blank entries (role-agnostic), and StartupValidator requires a Site node to
list >=1 endpoint (fail-fast, mirrors GrpcPsk). Rig configs moved
CentralContactPoints -> CentralGrpcEndpoints (docker x6, docker-env2 x2, Host default,
deploy/wonder-app-vd03). Kept Akka.Cluster.Tools (ClusterSingleton still used).
Tests: build 0/0; Communication.Tests 640, Host.Tests 421 green. Removed the
ClusterClient.Send per-site-routing tests (covered by the transport suites), swapped
the ISiteClientFactory-based ctors to a substitute ISiteCommandTransport, converted
the audit-push integration relay to an in-process bridge transport.
Docs: Component-Communication/Host/StoreAndForward, components/Communication,
topology-guide, grpc_streams (SUPERSEDED note), the frame-size known-issue (retired
amendment), and CLAUDE.md transport decisions.
Not included: the dead IntegrationCallRequest path (#32) is a separate user-owned
behavioral decision — SiteEnvelope routing is transport-agnostic so it still compiles.
Phase 0 of the ClusterClient→gRPC migration
(docs/plans/2026-07-22-clusterclient-to-grpc-plan.md). Standalone hardening: it
closes a gap that exists today and is a precondition for moving command/control
onto gRPC in later phases.
T0.1 — delete the ManagementActor ClusterClientReceptionist registration.
It was built for an out-of-cluster CLI that was never written: the shipped CLI
speaks HTTP Basic to /management, which asks the actor in-process through
ManagementActorHolder. Nothing in the repo ever sent to /user/management. The
actor still runs there; only the cross-boundary advertisement is gone. Six
documents claimed the CLI used ClusterClient — including the CLI's own README
"Architecture Notes" — and are corrected here rather than left to rot.
T0.2 — record, do not port, the dead integration-routing path.
IntegrationCallRequest is unwired at BOTH ends: RouteIntegrationCallAsync has
zero callers anywhere, and RegisterLocalHandler(Integration, …) appears only in
a test, so production always answers "Integration handler not available". It is
excluded from the gRPC contract (28 of 29 commands migrate) rather than
enshrined on an additive-only wire format, and deleting it during a
transport migration would mix a behavioural change into a change whose whole
value is that behaviour is identical. See
docs/known-issues/2026-07-22-integration-call-routing-is-dead-code.md.
T0.3 — preshared-key authentication on SiteStreamService.
The service shipped with no auth at all: plaintext h2c, no interceptor, so
anything that could reach a site node's :8083 could open a live data stream or
read audit rows back via PullAuditEvents/PullSiteCalls. ControlPlaneAuthInterceptor
now gates /sitestream.SiteStreamService/ — modeled on LocalDbSyncAuthInterceptor
(constant-time compare, fail-closed, PermissionDenied) but gating a SET of
service prefixes so phases 1A/1B add services rather than interceptors. LocalDb
sync keeps its own separate key: it authenticates the pair partner, not central,
and collapsing the two would make a site's central-facing key also admit writes
into its database.
Keys are per site (SB-GRPC-PSK-<siteId>), never fleet-wide, so a compromised
site yields only its own. Central attaches them through ControlPlaneCredentials,
which binds CallCredentials to the channel — covering unary and streaming
uniformly, and letting the key resolve asynchronously, which a client
interceptor could not do without blocking. All three central→site channel
creation sites go through it (SiteStreamGrpcClient and both audit pull invokers);
the pull invokers' channel caches are re-keyed by (site, endpoint) because
credentials are per-site and bound to the channel.
Two decisions beyond the plan:
* StartupValidator now requires GrpcPsk on Site nodes. The plan specified only
the runtime gate, but fail-closed with no boot check produces a node that
joins, answers heartbeats and reports healthy while refusing every stream,
audit pull and telemetry ingest — silent and total. Same reasoning as the
existing inbound API-key pepper rule.
* Added Communication:SitePsks as a central-side key map. The plan assumed
central would read the store, seeded via a dev KEK; the docker rig
deliberately boots with no master key, so store-only resolution would leave
it unable to dial its own sites. The store stays primary — it is the only
source that can serve a site added at runtime — with the map covering
key-less hosts and one-off pins. Neither source falling back to
"unauthenticated" is the invariant.
T0.4 — dev keys on both rigs and tests.
34 tests. The seven that matter most exercise a real in-process gRPC stack over
TestServer: the unit tests on either side of the wire would both stay green if
the halves disagreed, and gRPC refuses call credentials on a plaintext channel
by default — the UnsafeUseInsecureChannelCallCredentials opt-in is only provable
by making a real call. They confirm correct key passes on unary AND streaming,
wrong key and no-credentials both get PermissionDenied, and an unresolvable key
fails the call with nothing reaching the service.
OPERATIONAL: a site node upgraded to this build without a key will not boot.
That includes the gitignored deploy/wonder-app-vd03/ overlay.
Every node now lists ITSELF as seed-nodes[0] and its partner second. Akka runs
FirstSeedNodeProcess -- the only bootstrap path that can form a NEW cluster when
no peer answers InitJoin -- exclusively for seed-nodes[0]; every other node runs
JoinSeedNodeProcess and retries InitJoin forever. That is why a lone cold-starting
central-b never came Up (the "registered outage gap"), and self-first ordering
closes it using Akka's own protocol.
- 6 node appsettings swapped (the *-node-b configs; the -a nodes were already
self-first). All 14 shipped node configs now satisfy the invariant.
- StartupValidator enforces it at boot, comparing host AND port -- the invariant
fails silently when broken, so it is enforced loudly. NOTE: the gitignored
deploy/wonder-app-vd03/ overlay must be reordered before its next deploy or
that node will refuse to boot.
- SelfFirstSeedBootstrapTests: real in-process clusters at production
failure-detection timings, incl. a falsifiability control proving the OLD
peer-first ordering never forms.
Rejected alternative (implemented, measured, discarded): an external self-form
timer calling Cluster.Join(SelfAddress) after a window. It sits outside Akka's
join handshake and so cannot tell "no seed answered" from "a seed answered and
the join is in flight". On a routine standby restart the peer is alive but the
join stalls behind removal of the node's own stale incarnation; a Join(self)
during TryingToJoin abandons the in-flight join and forms a second cluster at
the same address -- still split after 90s. Docs that claimed self-first ordering
was unsafe for simultaneous cold start are corrected: while mutually reachable
the InitJoin handshake converges them to one cluster (measured).
Two-node keep-oldest could NEVER survive a crash of the oldest/active node:
Akka.NET 1.5.62 KeepOldest.OldestDecision only lets down-if-alone rescue a
side with >= 2 members, so the 1-vs-1 survivor takes DownReachable and downs
ITSELF — proven live on the rig ('SBR took decision ... including myself')
before this change. static-quorum(1) is worse (IsTooManyMembers -> DownAll);
keep-majority just re-keys the fatal crash to the lowest address.
SplitBrainResolverStrategy gains 'auto-down' (new default): BuildHocon emits
Akka's AutoDowning provider with auto-down-unreachable-after = StableAfter.
The leader among the REACHABLE members downs the unreachable peer, so the
survivor takes over singletons and /health/active in ~25s regardless of which
node died. Accepted trade (explicit owner decision): a real network partition
runs dual-active until an operator restarts one side. keep-oldest remains
supported; DownIfAlone validation is now scoped to it.
Live drill on the rebuilt rig: active-crash TAKEOVER in 28s (victim still
down; all 7 singletons Younger->Oldest), standby-crash removal 27s with 0
routing blips; victims rejoin as standby in 2s. New real-cluster tests pin
both directions (SbrFailoverTests.AutoDown_*); TwoNodeClusterFixture gains a
strategy knob. All 16 appsettings flipped (src, docker, docker-env2, and the
gitignored wonder-app-vd03 overlay on disk — owner must sync to the host).
Docs: decision record docs/plans/2026-07-21-auto-down-availability-decision.md,
Component-ClusterInfrastructure downing section rewritten, drill + README
reworked (active mode now asserts takeover), deferred-work SBR row resolved.
LocalDb Phase 2 deleted the bespoke replicators, so three config keys changed
meaning or died outright:
- ScadaBridge:StoreAndForward:ReplicationEnabled is fully dead. Deleted the
property, its 10 config entries, and the 5 test references.
- SqliteDbPath / SiteDbPath are now migration-only: they name the legacy files
SiteLocalDbLegacyMigrator drains at boot, not live databases. Both mandatory
rules are relaxed accordingly (StartupValidator's Site-only Require, and the
S&F validator's non-empty rule) — an absent value now means "nothing to
migrate", so an already-migrated node can drop the key. DatabaseOptions-
Validator still rejects a present-but-blank value.
- SiteRuntime:ConfigFetchRetryCount's only reader was SiteReplicationActor.
Deleted with its validator rule.
The two path keys stay present in every config, now with a comment explaining
why: removing them would strand un-migrated data on a node that has not yet
started once.
Both relaxations are pinned by the inverse of the test they replace
(Site_MissingSiteDbPath_IsAccepted..., EmptySqliteDbPath_IsAccepted...), each
verified to fail with the old rule restored.
Note: deploy/wonder-app-vd03/appsettings.Site.json is under a gitignored
deploy/ tree, so its edit is local-only and must be repeated on the box.
Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts
Task 3. Site nodes now open one ZB.MOM.WW.LocalDb-managed database holding
OperationTracking and site_events as replicated tables.
SiteLocalDbSetup.OnReady applies both schemas and then RegisterReplicated's them.
That order is load-bearing and easy to get silently wrong: capture is
trigger-based CDC, so rows written before registration are never captured or
snapshotted - they would be invisible to the peer forever, with no error anywhere.
Storage ships UNCONDITIONALLY, no feature flag. With no peer configured LocalDb is
just a local SQLite file, so this is behaviour-equivalent to what site nodes do
today. Replication is opt-in and lands in Program.cs (Task 7), which owns the gRPC
host the sync endpoint needs.
Config: LocalDb:Path added to all EIGHT site-node appsettings (the plan said six -
docker-env2's site-x pair exists too), plus the dev template and the wonder-app-vd03
production sample. All ten are required, not optional: LocalDbOptions.Path is
validated with ValidateOnStart, so a site node without it fails fast at startup.
That is the desired posture, and it is what caught ActorPathTests - the one Host
fixture that actually starts a host - whose config now sets the path too.
Note the path choice fixes an existing data-loss bug in passing: site-tracking.db
and site_events.db both defaulted to CWD-relative paths (/app/...), outside the
mounted volume, so they were silently lost on every container recreate. The
consolidated database lives on /app/data.
Tests are container-built against the REAL SiteServiceRegistration.Configure, not a
hand-assembled ServiceCollection - this family has shipped three wiring defects that
only a real graph would catch (inert Secrets replicator 0.2.0, singleton deadlock
0.2.2, Secrets.Ui missing IAuditWriter). They assert the library's own view of what
is registered rather than that we called the right method.
Verified (all after the change):
dotnet build ZB.MOM.WW.ScadaBridge.slnx -> 0 Error(s), 0 Warning(s)
Host.Tests -> 294 passed (5 new, red-first)
SiteRuntime.Tests -> 530 passed
CentralUI.Tests -> 925 passed
Commons.Tests -> 684 passed
Communication.Tests -> 312 passed
SiteEventLogging.Tests-> 70 passed
Claude-Session: https://claude.ai/code/session_01BL2Vu1ESDQ9SCN4gVKkdts
Populates ScadaBridge:Communication:CentralFetchBaseUrl in every central
appsettings for the notify-and-fetch deploy flow. An empty value now
causes a fail-fast on deploy; this config prevents that regression.
- docker/: http://scadabridge-traefik (in-network Traefik LB, port 80)
- docker-env2/: http://scadabridge-env2-traefik (env2 Traefik LB, port 80)
- src/Host base: http://localhost:5000 (ASP.NET Core default for single-host dev)
- deploy/wonder-app-vd03: http://localhost:8085 (gitignored; edited in main repo)
RUNBOOK Upgrading section updated with note on this setting.
Wire the M6 KPI History recorder into the central composition path:
- Program.cs: call services.AddKpiHistory(configuration) on the central-only
branch alongside AddNotificationOutbox/AddAuditLog/AddSiteCallAudit.
- AkkaHostedService.cs: register KpiHistoryRecorderActor as a central,
non-role-scoped ClusterSingletonManager + ClusterSingletonProxy + a
PhaseClusterLeave CoordinatedShutdown graceful-stop drain (singleton name
'kpi-history-recorder'), copied/adapted from the audit-log-purge block.
- appsettings.Central.json (Host + docker + docker-env2 central nodes): add a
ScadaBridge:KpiHistory section (SampleInterval 00:01:00, RetentionDays 90,
PurgeInterval 1.00:00:00, DefaultMaxSeriesPoints 200).
KPI history is observability/best-effort and MUST NOT gate readiness: the
recorder is deliberately NOT added to RequiredSingletonsHealthCheck or any
other readiness gate.
Both :9000 (docker) and :9100 (docker-env2) central nodes now bind the shared dev
GLAuth (scadaproj/infra/glauth/, dc=zb,dc=local) via the cn=serviceaccount search
account instead of the bundled scadabridge-ldap container (now commented out in
infra/docker-compose.yml, kept for rollback). Verified: multi-role -> all 4 roles
on both clusters with scadabridge-ldap stopped.
The auth cookie name was hardcoded to ZB.MOM.WW.ScadaBridge.Auth. Because
browser cookies are scoped by host+path but NOT by port, two ScadaBridge
clusters on the same host (the local docker stack on localhost:9000 and
docker-env2 on localhost:9100) shared one cookie jar: signing into one
overwrote the other's cookie, and since the clusters use different JWT
signing keys + separate Data Protection key rings, the overwritten side
could no longer validate its cookie and the session died.
Add SecurityOptions.CookieName (default = canonical ZB.MOM.WW.ScadaBridge.Auth,
blank falls back to the default) applied via the SecurityOptions-bound cookie
PostConfigure. Override it to ...Auth.env2 in both docker-env2 Central nodes so
the two local clusters no longer collide; the primary cluster keeps the default
so its live sessions and production are unaffected. Adds 3 Security.Tests cases.
The Auth/Config normalization made ScadaBridge:InboundApi:ApiKeyPepper a hard
Central-only startup requirement (>=16 chars), but the local dev composes never
supplied it, so deploy.sh's freshly-built image crash-looped both Central nodes
on ConfigPreflight validation. Add a clearly-marked DEV-ONLY, insecure pepper
inline to each cluster's Central environment (distinct per environment). These
are NOT real secrets — production injects a true per-env secret out-of-band per
docs/operations/inbound-api-key-reissue.md; the inline values exist only so the
local docker / docker-env2 clusters start.
Replace dc=scadabridge,dc=local with dc=zb,dc=local in all dev/test LDAP
references — app config, docker test-cluster node configs (docker/ and
docker-env2/), GLAuth fixture, dev tooling, Host.Tests fixtures,
IntegrationTests factory, and operational test_infra docs. OU structure
(ou=SCADA-Admins,ou=users,etc.) preserved throughout. Email domains
(@scadabridge.local), hostnames, and container names are untouched.
Historical plan docs (2026-05-24-second-environment.md,
2026-05-31-folder-repo-rename-scadabridge-design.md) excluded as
point-in-time records. No synthetic dc=example,dc=com placeholders touched.
Renames the 13 SCADALINK_* runtime env vars → SCADABRIDGE_*, the ScadaLink__
.NET config keys → ScadaBridge__, the stale ScadaLink.Host.exe assembly name
→ ZB.MOM.WW.ScadaBridge.Host.exe, the scadalink_app SQL login → scadabridge_app,
and residual identifiers/comments/docs. Migration records (prior rename
tooling/design, DB-rename helper, this scrub script) carved out.
Adds tools/scrub-scadalink-refs.sh.
Replace the generic 'MxGateway Shared' connection name with a per-site name
(site-a -> 'ScadaBridge Site A', env2 site-x -> 'ScadaBridge Site X') in both
docker/ and docker-env2/ seed scripts.
Test instances persistently emit Notify.To("Engineering Alerts").Send;
without the list at central a fresh cutover parks every notification
(observed 42k+ parked in a 3.5-min S&F drain after the rename).
Mirror the seed across docker/seed-sites.sh and docker-env2/seed-sites.sh.
A fresh ScadaBridgeConfig has only the Admin LdapGroupMappings row
(InitialSchema migration ships one row, SecurityConfiguration.HasData
declares four). docker-env2/seed-sites.sh already inserts the missing
three idempotently; docker/seed-sites.sh did not, so multi-role got
Admin only on a primary cutover. Mirror the env2 insert block.
SecurityConfiguration.HasData declares 4 LdapGroupMapping seed rows
(Admin / Design / Deployment-All / Deployment-SiteA) but the
InitialSchema migration only INSERTs the Admin row -- the other three
were never captured into a migration. A fresh ScadaLinkConfig2 starts
with multi-role getting Admin only, no Design or Deployment access.
(The same divergence exists on primary's ScadaLinkConfig, but it has
the rows from earlier history.)
Insert the missing three idempotently from seed-sites.sh so env2's
fresh deploys end up role-aligned with the running primary cluster.
The longer-term fix is a new EF migration that captures the HasData
diff -- intentionally not done here to avoid touching the primary
cluster's existing rows.
Joseph Doherty