GitLab CI/CD

GitLab, while initially recognized as a web-based Git repository manager, has evolved into a comprehensive DevOps platform. One of its standout features is the Continuous Integration/Continuous Deployment (CI/CD) system. GitLab CI/CD offers an integrated approach to automating the release pipeline, from code commit to production deployment.

What is CI/CD?

To understand how GitLab CI/CD works and what it does, it’s a good idea to make sure that you understand the concepts associated with CI/CD.

Continuous Integration (CI) is the practice of frequently integrating code changes into a shared repository. Once the changes are in the repository, automated builds and tests are run. Continuous Deployment (CD) takes this a step further, automating the deployment process to get changes live, ensuring faster, systematic, and repeatable deployments.

The video below, from the Fireship YouTube channel, gives a quick visual and technical overview of the concepts used in CI/CD.

Key Features of GitLab CI/CD

1. Integrated with Git Repositories: GitLab CI/CD is integrated into GitLab’s SCM (source code management) system. This makes it easier to handle CI/CD for projects hosted on GitLab without needing third-party integrations.
2. Pipeline Visualizations: Users can view pipelines graphically, observing the status of individual jobs, and even stages.
3. Docker Integration: GitLab Runner, the open-source project powering GitLab CI/CD, can execute jobs in Docker containers, making builds reproducible.
4. Matrix Builds: GitLab CI/CD supports matrix builds, which allows running tests on multiple machines, spanning different versions and configurations.
5. Auto DevOps: With Auto DevOps, GitLab automatically configures CI/CD pipelines, monitoring, and deployments, lessening the configuration burden.
6. Customizable: Users can define custom pipeline structures, specifying stages, jobs, and the order in which they should run.
7. Built-in Container Registry: GitLab offers an integrated container registry to store Docker images, facilitating smoother deployments.

How GitLab CI/CD Works

The backbone of GitLab CI/CD is the .gitlab-ci.yml file. This YAML file describes the build and deployment pipeline, specifying jobs, stages, and execution rules. Whenever code changes are pushed to the repository, GitLab references this file to run the corresponding CI/CD jobs.

How GitLab CI/CD Handles Pipeline Release Automation

The table below presents the various concepts involved with Continuous Integration/Continuous Deployment and describes how GitLab CI/CD handles the different facets of CI/CD.

Getting Started with GitLab CI/CD

1. Set up GitLab Runner:

GitLab Runner is responsible for executing the jobs. It can run on various systems, and it interfaces with GitLab CI/CD.

• Install GitLab Runner:Follow the installation guidelines for your OS from the official documentation.
• Register the Runner:bashCopy codegitlab-runner register This command initiates a prompt for GitLab’s instance URL, the registration token (found in your project’s CI/CD settings), a description, and the desired executor (e.g., shell, docker).

2. Define Your CI/CD Pipeline:

Create a .gitlab-ci.yml file in the root directory of your project. A basic pipeline might look like:

yamlCopy codestages:
  - build
  - test
  - deploy

build_job:
  stage: build
  script:
    - echo "Building the project..."

test_job:
  stage: test
  script:
    - echo "Testing the project..."

deploy_job:
  stage: deploy
  script:
    - echo "Deploying the project..."

3. Push the Configuration:

Commit the .gitlab-ci.yml file and push it to your GitLab repository:

bashCopy codegit add .gitlab-ci.yml
git commit -m "Add CI/CD configuration"
git push origin master

4. Monitor the Pipeline:

Once you’ve pushed the configuration, GitLab will automatically recognize the file and initiate the CI/CD process. Navigate to the CI/CD section of your project in GitLab’s web interface to monitor the pipeline’s progress.

Conclusion

GitLab CI/CD is a powerful, integrated solution to streamline software release processes. With its wide range of features and tight integration with GitLab’s other offerings, it has become an essential tool for teams aiming for efficient, automated, and error-free deployments.