docker-compose.yml reference · Knowledge & Memory Center

Full example

A typical API + database + cache stack. The file is usually named compose.yaml or docker-compose.yml; the top-level version: key is obsolete.

compose.yaml

YAML

1services:

2 api:

3 build:

4 context: .

5 dockerfile: Dockerfile

6 args:

7 APP_VERSION: 1.4.2

8 image: myorg/api:1.4.2

9 ports:

10 - "8080:8080" # host:container

11 env_file: .env

12 environment:

13 DB_HOST: db # service name = hostname

14 SPRING_PROFILES_ACTIVE: prod

15 depends_on:

16 db:

17 condition: service_healthy

18 restart: unless-stopped

19 deploy:

20 resources:

21 limits: { cpus: "1", memory: 512M }

23 db:

24 image: postgres:16-alpine

25 environment:

26 POSTGRES_PASSWORD: ${DB_PASSWORD} # from .env

27 volumes:

28 - pgdata:/var/lib/postgresql/data

29 healthcheck:

30 test: ["CMD-SHELL", "pg_isready -U postgres"]

31 interval: 5s

32 retries: 10

34 cache:

35 image: redis:7-alpine

36 profiles: ["cache"] # only starts with --profile cache

38volumes:

39 pgdata:

Key fields

Key	Meaning
`image` / `build`	Use an existing image, or build one (both = build and tag it)
`ports`	Publish to the host; omit for internal-only services
`expose`	Document internal ports only
`environment` / `env_file`	Env vars; `${VAR}` is substituted from `.env` or the shell
`volumes`	Named volumes or `./relative` bind mounts
`depends_on`	Start order; add `condition: service_healthy` to wait for readiness
`restart`	`no`, `always`, `on-failure`, `unless-stopped`
`command` / `entrypoint`	Override the image CMD / ENTRYPOINT
`profiles`	Optional services, enabled with `--profile`
`networks`	Custom networks (a default one is created per project)

Tip

Keep a base compose.yaml plus a compose.override.yaml for local development (bind mounts, debug ports); Compose merges the override automatically. Check the final result with docker compose config.