How do I run Linux tasks without Docker (on the underlying system)?

Question

Tasks image_resource property is marked as optional in the documentation , but GNU/Linux tasks fail without it.

Also, the docs for the type property of image_resource say:

Required. The type of the resource. Usually docker-image

But I couldn't find any information about other supported types.

How can I run tasks on the underlying system without any container technology, like in my Windows and macOS workers?

Answer 1

In Concourse, you really are not supposed to do anything outside of Docker. That is one of the main features. Concourse runs in Docker containers and starts new containers for each build. If you want to run one or more Linux commands in sh or bash in the container, you can try something like this below, for your task config.

  - task: linux
    config:
      platform: linux
      image_resource:
        type: docker-image
        source: {repository: ubuntu, tag: '18.04'}
      run:
        dir: /<path-to-dir>
        path: sh
        user: root
        args:
          - -exc
          - |
            echo "Running in Linux!"
            ls
            scp <you@your-host-machine:file> .
            telnet <your-host-machine>
            <whatever>
            ...