GeezerVison

db-only-migrate.docker-compose.yaml starts only the databases, so nothing else is connected to them during a backup or restore. It had two problems:

• It left out codeinsights-db. The backup and restore docs start this file, then run docker exec codeinsights-db ... pg_dump. That container was not running, so the step failed.
• It had drifted. It was a hand-made copy of pgsql and codeintel-db, under a "MUST be kept in sync" comment, and no longer matched docker-compose.yaml.

It now uses extends for all three databases, so it cannot drift. extends copies one service's settings. It does not start any other service from docker-compose.yaml, so the file starts exactly three containers: pgsql, codeintel-db, and codeinsights-db.

What customers will see

codeinsights-db now starts, on the same codeinsights-db volume the full deployment uses.

pgsql and codeintel-db start with the same settings as in the full deployment:

Risk: low to medium. Customers run this file during upgrades, backups, and restores. The databases get the settings they already have in the full deployment, on the same volumes.

Checklist

• All images have a valid tag and SHA256 sum (no image changes)

Test plan

• docker compose -f db-only-migrate.docker-compose.yaml config --services lists pgsql, codeintel-db, and codeinsights-db, and nothing else (Compose 2.18.1 and 5.7.1). On main it lists the first two

• Each of the three resolves to the same configuration from this file and from docker-compose.yaml. On Compose 5.7.1 the output is identical; on 2.18.1 it lists each service's two mounts in the other order

• Ran the backup steps from the docs on a test machine (Docker 29.9.3, Compose 5.7.1): a full deployment, down, then this file alone on the same volumes

  	main	This PR
  Containers started	pgsql, codeintel-db	pgsql, codeintel-db, codeinsights-db; healthy in 6 seconds, nothing else running
  Other clients connected to the databases	0	0
  The three pg_dump commands from the docs	The third fails: No such container: codeinsights-db	All three exit 0
  docker compose -f docker-compose.yaml run --rm --no-deps migrator	Fails: lookup codeinsights-db ... no such host	Schema(s) are up-to-date!

• Restoring this PR's three dumps into empty volumes brings back the same row counts

• Build: build 16870: passed, the smoke test job took 507 seconds. After the rebase onto the 8.2.0 images, build 16903 passed in 458 seconds

Closes FE-580