CODEWITHSUNDEEP
dockerdocker-composedockerfile
Vipin Menon
Vipin Menon

Reputation: 3302

Adding default external network in docker-compose

I am trying to learn docker and understanding docker-compose

As I was trying out the external network section:

 networks:
  default:
    external:
      name: my-pre-existing-network

I understand that 'my-pre-existing-network' needs to be created.

Is it possible to create a new default external network from within the compose file itself?

This is more from a learning/understanding perspective And also alternative to the docker network create command. Thanks.

Upvotes: 9

Views: 28722

Answers (4)

Marin
Marin

Reputation: 71

First of all, check your version of the file. For version 3.6, the following examples can meet your needs:

Example 1:

version: '3.6'
services:
  webserver:
...
#add existing database network 
networks:
  default:
    external:
      name: proxy_host

Example 2:

version: '3.6'
services:
  webserver:
...
#add existing database network 
networks:
  default:
    name: proxy_host
    external: true

Example 3: This configuration creates new networks.

version: '3.6'
services:
  webserver:
    networks:
      - proxy_host
      - database_host
...
networks:
  proxy_host: {}
  database_host: {}

Upvotes: 7

Dagistan
Dagistan

Reputation: 39

Maybe someone still looking for answer. Probably this will work.

version: '3.8'
services:
  api:
    networks:
      - test

networks:
   test:
    driver: bridge
    external: true

Upvotes: 3

masseyb
masseyb

Reputation: 4132

Ref. the "use a pre-existing network" documentation: "Instead of attempting to create a network called [projectname]_default, Compose looks for a network called my-pre-existing-network and connect your app’s containers to it." - docker-compose will not attempt to create the network.

The external network must already exist (e.g. "my-pre-existing-network"), it could be a docker network created from a different docker-compose environment or a docker network created using the docker network create command.

Note: docker-compose networks are prefixed with COMPOSE_PROJECT_NAME. You can use docker network ls to list existing networks.

Upvotes: 2

Farzad Vertigo
Farzad Vertigo

Reputation: 2818

In case you create a network within your compose-file then that one is not considered to be "external". You can create a custom network using network section:

version: '3'

services:
    my-service:
    # can be a pre-built image like this or built locally (check reference)
        image: some-image:latest 
        networks:
            - custom-network

networks:
    custom-network:
        driver: bridge

If you are going to use your compose file with swarm, you might want to choose driver: overlay. Additional information can be found here.

Upvotes: 3

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