Docker - Dont see mongoDB image after docker-compose build-CodePudding

I am doing my first steps with docker compose and made a docker-compose.yml file which contains:

version: "3.8"

services:
  web:
    build: ./frontend
    ports:
      - "3000:3000"
  api:
    build: ./backend
    ports:
      - "3001:3001"
    environment:
      DB_URL: mongodb://db/slip
  db:
    image: mongo:4.0-xenial
    ports:
      - "27017:27017"
    volumes:
      - slip:/data/db

volumes:
  slip:

However after running $ docker-compose build This is my result images in docker:

REPOSITORY   TAG                  IMAGE ID       CREATED              SIZE
slip_api    latest               445199e1e418   43 seconds ago       184MB
slip_web    latest               c1168ad560b8   About a minute ago   299MB
node         14.16.0-alpine3.13   50bfd284aa0d   10 months ago        117MB

I am not sure why I don't see the mongo:4.0-xenial image, and also not sure why I see the node:14.16.0-alpine3.13 which is a base (FROM) in docker file of the slip_api and slip_web and not an image by itself that I built.

Using Ubuntu 20.04.3 LTS

Thanks for the help!

CodePudding user response：

docker-compose build does literally that: it builds images. In order for an image to be built, the base image needs to present. That is the reason, why you are seeing the node image present.

You do not see the mongoDB image, because it is not built. Once you attempt to docker-compose up it will pull the latest version of mongo:4.0-xenial