How can I use Docker with GitLab CI?

How can I use Docker with GitLab CI?

You can use Docker in GitLab CI by defining a Docker image in your .gitlab-ci.yml file. This allows you to run your CI jobs in a containerized environment.

Can you show me a sample .gitlab-ci.yml file?

Sure! Here's a simple example:

image: docker:latest

services:
  - docker:dind

stages:
  - build

build:
  stage: build
  script:
    - docker build -t my-image:latest .

What if I need to push the Docker image to a registry?

You can add a job to push the image to a registry like this:

push:
  stage: deploy
  script:
    - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    - docker push my-image:latest

Are there any best practices for using Docker in GitLab CI?

Yes, some best practices include using specific image tags, caching layers to speed up builds, and cleaning up unused images to save space.