尝试将数据持久化到卷时出现docker-compose.yml错误

Question

In my Docker Instance, I created a volume called jokes . I'm trying to build out my service now with docker-compose up but I keep getting this error message:

ERROR: The Compose file './docker-compose.yml' is invalid because:
services.db.volumes contains an invalid type, it should be an array

Here is my docker-compose.yml file:

version: '3.6'
services:
  web:
    build: .
    command: puma
    depends_on:
      - db
    environment:
      DATABASE_URL: "postgres://postgres@db"
    ports:
      - "3000:3000"
    volumes:
      - "./:/app"
    working_dir: /app
  db:
    image: "postgres:10.3-alpine"
    volumes: "-jokes: /var/lib/postgresql/data"
volumes:
  jokes: ~

How should I fix this?

Answer 1

How should I fix this?

As detailed in the official documentation you are required to give a list there (hence complaint about list), so move hyphen outside the quotes like so:

volumes: 
  - "jokes:/var/lib/postgresql/data"