What is the purpose of the .gitlab-ci.yml file in GitLab CI/CD?

The .gitlab-ci.yml file plays a crucial role in GitLab CI/CD by defining the pipeline stages, jobs, and the specific actions to execute during the CI/CD process. This file acts as the blueprint for automation in the continuous integration and continuous deployment workflows. Within it, you can specify single or multiple jobs that detail how to build, test, and deploy your applications, as well as configure various stages in the pipeline, such as build, test, and deploy.

By structuring the CI/CD pipeline in this manner, teams can automate their development processes efficiently, ensuring that code changes are tested and deployed consistently and reliably. This not only enhances the quality of the code but also speeds up the release cycles, making it essential for DevOps practices.

Other choices refer to different aspects: while the GitLab Runner does rely on configurations, it is not specifically outlined in the .gitlab-ci.yml. Project documentation can be maintained separately and is not the primary purpose of this file, and deploying applications to Kubernetes is a specific action that can be defined within the .gitlab-ci.yml but is not the overarching purpose of the file itself.