Communication between multiple docker-compose projects

Question

I have two separate docker-compose.yml files in two different folders:

• ~/fp/docker-compose.yml
• ~/ap/docker-compose.yml

How can I make sure that a container in fp can send requests to a container in ap?

Answer 1

You just need to make sure that the containers you want to talk to each other are on the same network. Networks are a first-class docker construct, and not specific to compose.

# fp/docker-compose.yml
version: '2'
services:
  front:
    ...
    networks:
      - some-net
networks:
  some-net:
    driver: bridge
...
# ap/docker-compose.yml
version: '2'
services:
  api:
    ...
    networks:
      - front_some-net
networks:
  front_some-net:
    external: true

They can then talk to each other using the service name. From frontyou can do ping api and vice versa.

Answer 2

Small addition to @kalgi's answer..

While running a docker compose file, a default network is created which can be added to the with other network file as an external network.

# fp/docker-compose.yml
version: '2'
  services:  
    front_service:
    ...

...

# ap/docker-compose.yml
version: '2'
services:
  api_service:
    ...
    networks:
      - front_default
networks:
  front_default:
    external: true

Answer 3

This worked for me:

version: "3.5"
services:
  proxy:
    image: user/image:tag
    ports:
      - "80:80"
    networks:
      - proxynet

networks:
  proxynet:
    name: custom_network

Answer 4

Another approach is to compose both the containers to the same network by composing them at the same time. Something like this:

docker compose --file ~/front/docker-compose.yml --file ~/api/docker-compose.yml up -d