docker compose: a stack in one file

A stack is taken down with one command. Here: what stays after it.

A service connects a named volume by name, and the volume itself is declared at the top level of the file — with the volumes: key next to services:. compose prefixes the volume name with the project name: the volume pgdata of the project shop is called shop_pgdata.

yaml

services:
  db:
    image: busybox
    volumes:
      - pgdata:/data     # a project volume
volumes:
  pgdata:

docker compose down stops and removes the project's containers and its network. The volumes stay: the data outlives re-creating the stack. To remove them along with the stack — docker compose down -v.

Check yourself 1 question

~/notes/compose.yaml declares the volume notes-data. The stack was taken down with sudo docker compose down. What will sudo docker volume ls show?

compose prefixes the volume name with the project name, the notes directory: the volume is called notes_notes-data.
notes_default is the project's network, and down removes it. sudo docker network ls lists networks, sudo docker volume ls lists volumes.
down removes the project's containers and network but keeps the volumes. docker compose down -v removes the stack together with its volumes.

down removes the project's containers and network and keeps its volumes, so the data outlives re-creating the stack. compose built the volume name from the project name and the name in the file: notes_notes-data.

Key points

A named volume is declared with the top-level volumes: key and is called <project>_<volume>.
down removes the project's containers and network; the volumes stay.
down -v removes the volumes along with the stack.

docker compose: a stack in one file

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