CODEWITHSUNDEEP
dockerdocker-compose
Muthaiah PL
Muthaiah PL

Reputation: 1158

DockerCompose build one image and run multiple containers

I have a docker-compose file which builds 4 images and runs 4 containers which is fine. But in those 4 Dockerfile which I used to build 4 images, the only difference is that the cmd. I'm just wondering if there's a better way of doing this like build one image and run 4 containers from that image just by changing the cmd,

Here is my docker-compose.yml

version: '3.6'

services:
  esg_scoring.insight:
    build:
      context: .
      dockerfile: insight/Dockerfile
  esg_scoring.momentum:
    build:
      context: .
      dockerfile: momentum/Dockerfile
  esg_scoring.pulse:
    build:
      context: .
      dockerfile: pulse/Dockerfile
  esg_scoring.sasb_mapping:
    build:
      context: .
      dockerfile: sasb_mapping/Dockerfile

Upvotes: 2

Views: 3976

Answers (1)

DannyB
DannyB

Reputation: 14776

In case you need multiple containers running the same image, and differing only by the command that starts them, you should most definitely avoid multiple docker images, and use the same image.

The command directive in docker-compose is what you are looking for.

In addition, you can use the YAML anchors syntax to reuse code blocks and simplify your code.

Here is an example of having 4 services, using the same image, with different commands. You can put all the arguments that are common to all, under the default setting:

services:
  bash:
    build: .
    command: bash
    <<: &default
      image: me/my-image

  web:
    <<: *default
    command: bundle exec run server start

  setup:
    <<: *default
    command: bundle exec run db setup

  jobs:
    <<: *default
    command: bundle exec run job runner

The nice thing about this approach, is that it will only build once when you run docker-compose build, since the build directive is outside of the default setting.

Upvotes: 7

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