Use gitlab-runner and dind (Docker-in-Docker) on MacOS

What I learned today — 30 September 2018

Install:

To test your .gitlab-ci.yml locally on MacOS (I’m using High Sierra) you need the following:

• Docker
• gitlab-ci-multi-runner

After installing Docker, install the runner using brew:

brew install gitlab-ci-multi-runner

Set up .gitlab-ci.yaml:

Your CI file might look something like this:

image: docker:latest
services:
  - docker:dind

variables:
  DOCKER_DRIVER: overlay

stages:
  - build

docker-build:
  stage: build
  script:
  - docker build -t registry.gitlab.com/my-username/my-project .
  - docker login -u gitlab-ci-token -p $CI_BUILD_TOKEN registry.gitlab.com
  - docker push registry.gitlab.com/my-username/my-project

Run locally before pushing:

gitlab-runner exec docker --docker-privileged docker-build

Let’s unpack the above:

• exec Test your .gitlab-ci.yml locally using the “exec” command
• docker Use the “docker” executor
• --docker-privileged Running dind (“Docker-in-docker”) requires the “privileged” flag