Docker compose port mapping

Question

I have a docker-compose yml file as in below

version: \'2\'
services:
  nodejs:
    build:
      context: .
      doc         


        

Answer 1

If you want to bind to the redis port from your nodejs container you will have to expose that port in the redis container:

version: '2'
services:
  nodejs:
    build:
      context: .
      dockerfile: DockerFile
    ports:
      - "4000:4000"
    links:
      - redis

  redis:
    build:
      context: .
      dockerfile: Dockerfile-redis
    expose:
      - "6379"

The expose tag will let you expose ports without publishing them to the host machine, but they will be exposed to the containers networks.

https://docs.docker.com/compose/compose-file/#expose

The ports tag will be mapping the host port with the container port HOST:CONTAINER

https://docs.docker.com/compose/compose-file/#ports