Skip to main content
In this guide, we’ll dive into the four essential GitLab CI/CD building blocks—Pipeline, Stages, Jobs, and Scripts—and show you how they collaborate to automate testing, building, and deployment. By the end, you’ll have a clear understanding of how to configure a robust .gitlab-ci.yml and choose the right pipeline type for your workflow.

​
CI/CD Core Components Overview

​
Pipeline

A pipeline is defined via a .gitlab-ci.yml file at the root of your repo and represents the blueprint for your CI/CD workflow.
Ensure your .gitlab-ci.yml lives in the repository root; otherwise GitLab won’t detect it.
See GitLab CI/CD YAML reference.
Key points:
  • Definition: YAML file named .gitlab-ci.yml.
  • Naming: Use workflow:name to assign a custom name shown in the Pipelines tab.
  • Triggers: Pipelines start on push, merge_request, schedule, or manual actions.
  • Conditions: Use rules to control when pipelines run.
Example: Run pipeline only on commits to main

​
Jobs

A job is the fundamental execution unit in a pipeline:
  • Execution: Runs on a GitLab Runner (shared or self-hosted).
  • Runner selection: Use tags to pick specific runners.
  • Stage assignment: Each job belongs to a defined stage.
Example: Selecting a specific runner
Keep sensitive data out of script blocks. Use CI/CD variables for secrets like tokens or credentials.

​
Scripts

The script section lists shell commands executed by the job:
  • Sequential execution: Commands run in order.
  • Common use cases: Install dependencies, build code, run tests, deploy artifacts, perform security scans.
  • Before/after hooks:
    • before_script: Setup steps (e.g., install Node.js, configure DB).
    • after_script: Cleanup tasks (e.g., remove temp files).

​
Example .gitlab-ci.yml

Here’s a complete sample that defines two stages—test and deploy—and a workflow rule:
In this configuration:
  • The pipeline runs only on main.
  • The test stage executes unit_test_job with setup, tests, and teardown.
  • The deploy stage runs deploy_job after successful tests.

​
Stages

Stages define the sequence of execution in a pipeline. Jobs within the same stage run in parallel. Common stages include:

​
Pipeline Types

The image lists different types of pipelines, including Basic Pipeline, DAG Pipeline, Merge Request Pipelines, Merged Results Pipelines, Merge Trains, Parent-Child Pipelines, and Multi-Project Pipelines. Each type is displayed in a colored box with an icon.
Choose the pipeline type that best suits your project complexity and team structure:

Watch Video