Concourse Docker-Compose-in-Docker

Optimized for use with Concourse CI.

The image is Alpine based, and includes Docker, Docker Compose, and Docker Squash, as well as Bash.

Image published to Docker Hub: karlkfi/concourse-dcind.

Inspired by meAmidos/dcind, concourse/docker-image-resource, and mesosphere/mesos-slave-dind.

Features

Unlike meAmidos/dcind, this image...

• Does not require the user to manually start docker.
• Uses errexit, pipefail, and nounset.
• Configures timeout (DOCKERD_TIMEOUT) on dockerd start to account for mis-configuration (docker log will be output).
• Accepts arbitrary dockerd arguments via optional DOCKER_OPTS environment variable.
• Passes through --garden-mtu from the parent Gardian container if --mtu is not specified in DOCKER_OPTS.
• Sets --data-root /scratch/docker to bypass the graph filesystem if --data-root is not specified in DOCKER_OPTS.

Build

docker build -t karlkfi/concourse-dcind .

Example

Here is an example of a Concourse job that uses karlkfi/concourse-dcind image to run a bunch of containers in a task, and then runs the integration test suite. You can find a full version of this example in the example directory.

jobs:
- name: integration
  plan:
  - get: code
    params:
      depth: 1
    passed:
    - unit-tests
    trigger: true
  - task: integration-tests
    privileged: true
    config:
      platform: linux
      image_resource:
        type: docker-image
        source:
          repository: karlkfi/concourse-dcind
      inputs:
      - name: code
      run:
        path: entrypoint.sh
        args:
        - bash
        - -ceux
        - |
          # start containers
          docker-compose -f code/example/integration.yml run tests
          # stop and remove containers
          docker-compose -f code/example/integration.yml down
          # remove volumes
          docker volume rm $(docker volume ls -q)