# The Compose Lifecycle — Docker Compose

Source: https://www.skillbyai.com/en/docker-compose/i-cli

> up, ps, logs, exec, down.

## Everyday commands

`docker compose up -d` builds images if needed, creates networks and volumes, and starts services in the background; `ps` lists them; `logs -f` follows combined logs; `exec <service> sh` opens a shell inside a running container; `run --rm <service> <cmd>` runs one-off tasks such as migrations; `down` stops and removes containers and networks (add `-v` to also delete named volumes, which deletes data). `config` prints the fully resolved configuration and validates it, without starting anything.

## A typical session (sketch)

Commands that start containers need a running Docker engine; not run here.

```bash
docker compose up -d --build        # build images and start in the background
docker compose ps                    # status and health of each service
docker compose logs -f api           # follow one service's logs
docker compose exec db psql -U shop  # shell into a running container
docker compose run --rm api npm run migrate   # one-off task
docker compose down                  # stop and remove containers + networks (volumes kept)
```

## Be careful with down -v

down -v deletes named volumes, including database data; use it only when you mean to reset.

**Quiz:** Which command removes containers AND deletes named volumes?

- [ ] docker compose config
- [ ] docker compose stop
- [ ] docker compose ps
- [x] docker compose down -v

*Answer:* docker compose down -v. Volumes survive a plain down.