Redundant LDAP test pair (primary + backup "DC")

Two GLAuth containers on the dev Mac that simulate the NAM two-DC topology (uswap-vdc-nam1/nam2) for exercising ZB.MOM.WW.Auth.Ldap 0.2.x FallbackServers sticky failover. Deliberately local — the shared zb-shared-glauth on 10.100.0.35:3893 serves every other dev stack and must never be stopped for a drill.

	container	host port	from a container
primary	`zb-ldap-primary`	`3893`	`host.docker.internal:3893`
backup	`zb-ldap-backup`	`3894`	`host.docker.internal:3894`

Both mount the same config.toml — identical directory contents, like a real replicated pair. It is a copy of ../glauth/config.toml with one difference: the serviceaccount password here is the well-known local value serviceaccount123 (the shared instance's is rotated out-of-band, SEC-36). Same users otherwise (multi-role/password, etc.).

docker compose up -d          # start the pair

Consumer wiring (any of the four apps)

Ldap__Server: host.docker.internal        # primary
Ldap__Port: "3893"
Ldap__FallbackServers__0: host.docker.internal:3894
Ldap__Transport: None
Ldap__AllowInsecure: "true"

Wired consumers (both drilled PASS 2026-08-13):

HistorianGateway/docker/docker-compose.yml (Auth 0.2.1, dashboard login enabled). Note its Production-env container needs Serilog__WriteTo__0__Name: Console or it logs nothing — the drill's failover lines would be invisible.
ScadaBridge docker rig (docker/central-node-{a,b}/appsettings.Central.json, commit b71fbae3) — this pair REPLACED the shared 10.100.0.35 GLAuth there, whose serviceaccount password rotation (SEC-36) had silently broken rig login. ScadaBridge's AuthFlowTests also target localhost:3893 and pass 5/5 with the pair up (they skip when it is down).

Failover drill (verified PASS 2026-08-13 against HistorianGateway)

login → served by primary, no warnings
docker stop zb-ldap-primary → login OK; app logs WRN LDAP endpoint …:3893 failed system-side at connect + INF LDAP sticky preference moved to …:3894
docker start zb-ldap-primary → login OK, still served by the backup (sticky by design — verified by bind counts: primary got zero new binds)
docker stop zb-ldap-backup → login OK; warn on :3894, sticky moves back to :3893

The sticky preference lives in the app's singleton LdapAuthService, so an app restart resets it to the configured primary.