Adds a one-shot cluster-seed service to docker-dev/docker-compose.yml
that pre-populates the three Akka clusters' scope rows in the shared
OtOpcUa ConfigDb so operators don't have to click through /clusters +
/hosts on every fresh bring-up.
Seed contents:
ServerCluster MAIN (Warm/2), SITE-A (Warm/2), SITE-B (Warm/2)
ClusterNode driver-a + driver-b → MAIN
site-a-1 + site-a-2 → SITE-A
site-b-1 + site-b-2 → SITE-B
NodeCount + RedundancyMode honour the CK_ServerCluster check constraint.
ApplicationUri follows the urn:OtOpcUa:<NodeId> convention; uniqueness
across the fleet satisfies UX_ClusterNode_ApplicationUri.
Mechanism:
- docker-dev/seed/seed-clusters.sql — idempotent INSERTs (IF NOT EXISTS
guards on every row).
- docker-dev/seed/entrypoint.sh — bash wrapper that waits for SQL to
accept connections, then polls until dbo.ServerCluster exists (the
host containers' EF auto-migration creates it on first boot), then
applies the SQL script.
- cluster-seed service uses mcr.microsoft.com/mssql-tools as the base
image (bash + sqlcmd available), restart: "no" so it runs once.
Re-running `docker compose up` is safe: the seed exits cleanly on the
second run because every INSERT is guarded.
Manual re-seed: `docker compose run --rm cluster-seed`.
