Gitlab CICD Pipeline

When someone says they have built a CI/CD pipeline in GitLab, they mean they have created a process to automate the tasks involved in building, testing, and deploying an application. CI/CD stands for Continuous Integration (CI) and Continuous Deployment/Delivery (CD).

CI ensures that code changes are automatically built and tested when pushed to a repository.

CD automates the deployment of the application to staging or production environments.

Key Concepts of GitLab CI/CD:

1. GitLab Runner: A tool that executes the tasks defined in the pipeline.

2. .gitlab-ci.yml: The configuration file where the pipeline's stages, jobs, and steps are defined.

3. Stages: A pipeline is divided into stages like build, test, and deploy.

4. Jobs: Tasks within a stage, e.g., running tests, building Docker images, etc.

Summary of GitLab CI/CD Workflow

1. Define the Workflow:

A CI/CD pipeline is defined in a .gitlab-ci.yml file stored in your GitLab repository.

The file contains stages, jobs, and the steps to automate tasks like building, testing, and deploying.

1. Pipeline Trigger:

The pipeline is triggered automatically whenever code is pushed to the repository, or when a merge request is created.

1. Pipeline Stages:

Stages represent the sequence of tasks (e.g., build, test, deploy).

Each stage contains one or more jobs, which run specific tasks.

1. Jobs Execution:

Each job runs in its own isolated environment, using GitLab Runners (Docker, virtual machines, etc.).

Jobs execute scripts, run tests, build software, or deploy applications.

1. Parallel & Sequential Execution:

Jobs in the same stage run in parallel.

The pipeline moves to the next stage only if all jobs in the current stage pass.

1. Monitoring:

Pipeline progress is visible in the Pipelines section of the GitLab project.

Logs for each job can be reviewed to debug errors or verify success.

1. Artifacts:

Jobs can produce artifacts (e.g., built files, logs) that are stored and passed to subsequent stages.

1. Deployment:

The final stage deploys the application (e.g., to a server, database, or cloud environment).

GitLab supports manual approvals, environment configurations, and rollback mechanisms.

Flow Example:

1. Push Code → Pipeline starts automatically.

2. Stage 1 (Build): Compiles the application or validates syntax.

3. Stage 2 (Test): Runs tests to ensure functionality.

4. Stage 3 (Deploy): Deploys the application if all tests pass.

GitLab CI/CD ensures faster development cycles, automation of repetitive tasks, and improved code quality!