GitLab CI Best Practices for Microservices

After building CI/CD pipelines for 50+ microservices, these are the patterns that consistently deliver the best developer experience and security posture.

Pipeline Architecture

Use GitLab CI includes for reusable pipeline components:

# .gitlab-ci.yml include: - project: 'platform/ci-templates' file: '/pipelines/node-service.yml' ref: v2.1.0 variables: SERVICE_NAME: payment-api NODE_VERSION: "20"

Caching Strategy

Effective caching reduces pipeline time by 60-80%:

cache: key: ${CI_COMMIT_REF_SLUG} paths: - node_modules/ - .npm/ policy: pull-push build: cache: policy: pull

Security Scanning

Integrate security scanning at every stage:

stages: - validate - test - security - build - deploy sast: stage: security include: - template: Security/SAST.gitlab-ci.yml container_scanning: stage: security include: - template: Security/Container-Scanning.gitlab-ci.yml variables: CS_IMAGE: $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA

Deployment Patterns

Use environment-specific deployments with manual gates for production:

deploy:staging: stage: deploy environment: name: staging url: https://staging.example.com script: - helm upgrade --install $SERVICE_NAME ./chart --namespace staging --set image.tag=$CI_COMMIT_SHA deploy:production: stage: deploy environment: name: production url: https://example.com when: manual only: - main

Pipeline Optimization Tips

1. Use needs keyword for DAG-based pipeline execution
2. Run linting and unit tests in parallel
3. Use Docker layer caching with BuildKit
4. Set appropriate resource limits for runners
5. Use child pipelines for monorepo changes

Conclusion

Great CI/CD pipelines balance speed, security, and maintainability. Start with a solid template, measure pipeline duration, and iterate based on developer feedback.