Master GitLab CI/CD: From Basics to Automated Deployments

GitLab CI/CD Overview

GitLab CI/CD is an integrated tool in GitLab that enables Continuous Integration (CI), Continuous Delivery (CD), and Continuous Deployment (CD) to automate building, testing, and deploying applications.

How CI Works

Developers push small code changes to a Git repository; each push triggers scripts that build, test, and verify the code before merging into the main branch.

Continuous Delivery and Deployment

These extend CI by automatically deploying the application to production whenever changes are pushed to the default branch.

Configuration with .gitlab-ci.yml

The pipeline is defined in a .gitlab-ci.yml file placed at the repository root. GitLab Runner executes the scripts specified in this file.

before_script:
  - apt-get install rubygems ruby-dev -y
run-test:
  script:
    - ruby --version 6

Jobs are grouped into a pipeline; the example above installs dependencies and prints the Ruby version.

Pipeline Execution

When the .gitlab-ci.yml file is present, GitLab detects it and runs the defined jobs using a GitLab Runner, which can be a VM, physical machine, Docker container, or a cluster.

Runner Configuration

Runners communicate with GitLab via API; you can view or add runners under Settings → CI/CD .

Basic CI/CD Workflow

Push code to a branch → pipeline triggers.

Run automated scripts (build, test, review apps).

Merge feature branch to default branch → optional automatic deployment.

Rollback if issues arise.

CI/CD Stages

Verify : build, test, code quality, performance testing, container scanning, etc.

Package : store Docker images, NPM packages, Maven artifacts, Conan packages.

Release : continuous deployment, manual delivery, GitLab Pages, canary deployments, feature flags, releases, deploy boards, auto deploy to Kubernetes.

Auto DevOps

Auto DevOps provides predefined CI/CD configurations to automatically detect, build, test, deploy, and monitor applications, simplifying the full software lifecycle.

Kubernetes Deployment Example

Using GitLab’s native Kubernetes integration, you can create a project from a template, add a Kubernetes cluster, enable Auto DevOps, and deploy a Spring Boot application.

image: java:8
stages:
  - build
  - deploy
before_script:
  - chmod +x mvnw
build:
  stage: build
  script: ./mvnw package
  artifacts:
    paths:
      - target/demo-0.0.1-SNAPSHOT.jar
production:
  stage: deploy
  script:
    - curl --location "https://cli.run.pivotal.io/stable?release=linux64-binary&source=github" | tar zx
    - ./cf login -u $CF_USERNAME -p $CF_PASSWORD -a api.run.pivotal.io
    - ./cf push
  only:
    - master

Viewing Pipelines and Jobs

After configuring the runner, you can monitor pipeline status under CI/CD → Pipelines and view individual job logs under Pipelines → Jobs .

Conclusion

Define the .gitlab-ci.yml file, push it to the repository, and configure a runner to automate building, testing, and deploying your application, optionally leveraging Auto DevOps for a streamlined DevOps workflow.