Postgres

PostgreSQL is the default database for every architecture and the wizard's default answer. It backs the Ignition historian and any SQL-driven demo, and it is the one service that arrives with its gateway connection already wired up.

Image	postgres:18.1 (override with POSTGRES_IMAGE in .env)
Catalog kind	database
Provides	sql-database, postgres-compatible
Requires	nothing
Network when split is on	backend

How it reaches a stack

The wizard offers Postgres as the default answer to its database prompt, and the non-interactive ignition-stack create --arch <slug> path uses it unless you pick another database. The dependency resolver also adds Postgres automatically when another service needs a SQL database (for example Keycloak).

Credentials live in the shared database section of the generated .env (DB_USER, DB_PASSWORD, DB_HOST), so every database kind speaks one credential vocabulary. The defaults are ignition / ignition.

Seeding

Postgres is the only catalog database that seeds a working gateway connection. Its seed/gateway-resources/ overlay ships a db-connection (config plus resource.json) and the internal-secret-provider that holds the connection password as a JWE blob, so the gateway boots with a VALID database connection and no manual step. This follows the db-connection row of the seeding matrix, where both the config and the secret are file-seedable.

The other databases ship the container but leave the gateway-side connection to you to create in the UI once the stack is up.

Post-setup

None. The connection is live on first boot.