Top 60+ GitLab CI/CD Interview Questions with Real-World Use Cases Latest Updated

Top 60+ GitLab CI/CD Interview Questions with Real-World Use Cases Latest Updated

As of 2025, GitLab CI/CD is the most complete DevSecOps platform in the world — a single application for the entire software lifecycle with unmatched security, compliance, and AI-powered features (GitLab Duo Code Suggestions, Duo Vulnerability Explanation, Auto DevOps Score, and Value Stream Analytics). Used by NASA, Siemens, Goldman Sachs, and 50M+ developers, GitLab continues to dominate enterprise DevOps.

This ultimate interview guide contains 60+ real interview questions with detailed answers and production-grade use cases asked at FAANG-level companies, banks, and Fortune 500 organizations in 2025.

Why GitLab CI/CD in 2025?

• Single source of truth (repo + CI + security + CD + monitoring)
• Built-in SAST, DAST, Container Scanning, Dependency Scanning, License Compliance
• Auto DevOps, Review Apps, Canary & Blue/Green Deployments out-of-the-box
• AI-powered merge request summaries and root cause analysis
• Supports 2000+ concurrent runners, unlimited minutes on GitLab.com SaaS Premium+

Let’s dive in.

Top 60+ GitLab CI/CD Interview Questions & Answers (2025)

Basic to Intermediate (1–25)

1. What is .gitlab-ci.yml and where should it be placed? The pipeline configuration file written in YAML. Must be placed in the root of the repository.
2. What are the main keywords in GitLab CI? stages, jobs, script, image, services, before_script, after_script, artifacts, cache, rules, include, variables
3. Explain stages vs jobs. Stages = logical groups (e.g., build → test → deploy) Jobs = actual tasks that run in parallel within a stage
4. What is a GitLab Runner? Agent that executes jobs. Can be shared (GitLab-hosted) or specific (self-hosted on Kubernetes, Docker, shell, VM).
5. Difference between shared runners and group/project runners? Shared = managed by GitLab.com Group/Project = self-managed, full control over OS, tools, concurrency
6. How do you cache dependencies in GitLab CI?YAMLcache: key: ${CI_COMMIT_REF_SLUG} paths: - node_modules/ - .npm/
7. What are artifacts in GitLab CI? Files/directories passed between stages (reports, binaries, docker images). Real Use Case: Upload JUnit XML → show in Merge Request widget.
8. Explain rules vs only/except. only/except = deprecated rules = modern, more powerful (if, changes, exists, variables)
9. How do you trigger a pipeline manually?YAMLdeploy_prod: stage: deploy rules: - when: manual environment: production
10. What is the difference between script and before_script/after_script? before_script → runs before every job script → actual job commands after_script → runs even if job fails
11. How do you define global variables? Settings → CI/CD → Variables or in .gitlab-ci.yml:YAMLvariables: AWS_REGION: us-east-1
12. What are Review Apps? Dynamic environments created per branch/MR for QA/testing. Auto-destroyed on merge/close.
13. What is Auto DevOps? One-click full CI/CD: build → test → code quality → SAST → DAST → dependency scanning → review apps → staging → canary → production
14. How do you use Docker-in-Docker (dind)?YAMLservices: - docker:dind variables: DOCKER_HOST: tcp://docker:2376 DOCKER_TLS_CERTDIR: "/certs"
15. Explain GitLab CI/CD environments. Logical deployment targets (staging, production) with URL, protection, rollback support.
16. How do you promote artifacts between stages?YAMLartifacts: paths: - build/ expire_in: 1 week
17. What is include in GitLab CI? Import external YAML files (local, remote, template):YAMLinclude: - template: Security/SAST.gitlab-ci.yml - remote: 'https://example.com/template.yml'
18. How do you run jobs only on tags?YAMLrules: - if: '$CI_COMMIT_TAG'
19. What are protected variables? Masked and only available in protected branches/tags.
20. How do you implement parallel matrix jobs?YAMLtest: parallel: matrix: - OS: [ubuntu, windows] NODE: [16, 18, 20]
21. Explain needs keyword. Creates DAG (Directed Acyclic Graph) — jobs can start before previous stage finishes:YAMLdeploy: needs: ["build"]
22. What is GitLab Pages? Host static sites directly from repo (Hugo, Jekyll, Vue, etc.)
23. How do you trigger child pipelines?YAMLtrigger_job: trigger: include: child-pipeline.yml strategy: depend
24. What are pipeline triggers (bridge jobs)? Trigger downstream pipelines in another project:YAMLdownstream: trigger: project: mygroup/downstream-project
25. How do you implement Canary Deployments in GitLab? Use environments + manual jobs + weight (Kubernetes integration):YAMLcanary: environment: name: production url: https://canary.app.com kubernetes: weight: 10 # 10% traffic

Advanced & Real-World Use Cases (26–60+)

26. How do you implement Blue-Green deployment with GitLab + Kubernetes? Use two environments (blue/live, green/new), switch traffic via Ingress after smoke tests.
27. Explain GitLab Duo in CI/CD (2025). AI features:
    • Auto-generate pipeline code
    • Explain vulnerabilities in MR
    • Suggest test cases
    • Root cause analysis in failed pipelines
28. How do you run SAST/DAST automatically? Just include the Security templates:YAMLinclude: - template: Security/SAST.gitlab-ci.yml - template: Security/DAST.gitlab-ci.yml
29. How do you scan Docker images for vulnerabilities?YAMLinclude: - template: Security/Container-Scanning.gitlab-ci.yml
30. How do you enforce merge request approval rules based on pipeline status? Settings → Merge Requests → Require successful pipeline + code owner approval
31. What is Value Streams in GitLab? End-to-end DORA metrics (deployment frequency, lead time, MTTR, change failure rate)
32. How do you cache Docker layers to speed up builds? Use Docker BuildKit + cache export/import in GitLab CI
33. How do you implement compliance pipelines? Use compliance framework + required pipeline templates enforced at group level
34. How do you run jobs only when files change?YAMLrules: - changes: - Dockerfile - package.json when: always
35. What is interruptible keyword? Allows canceling old pipeline jobs when new commit arrives (saves runner minutes):YAMLtest: interruptible: true
36. How do you pass variables to child pipelines?YAMLtrigger: include: child.yml variables: ENV: prod
37. Explain GitLab Runner autoscaling on Kubernetes. Use GitLab Runner Operator + autoscaling config with min/max replicas based on queue length
38. How do you implement secret detection? Built-in job:YAMLinclude: - template: Security/Secret-Detection.gitlab-ci.yml
39. How do you use GitLab Feature Flags with CI? Integrate with Unleash or GitLab Feature Flags API to toggle features in staging/prod
40. How do you generate and publish code coverage badges?YAMLcoverage: '/Covered: \d+%/'
41. How do you implement database migrations safely? Use separate migration job with manual confirmation before running in production
42. What is GitLab CI/CD for Terraform? Use OpenTofu/Terraform templates + remote state in GitLab backend
43. How do you run performance tests only on main branch?YAMLperformance_test: rules: - if: '$CI_COMMIT_BRANCH == "main"'
44. How do you integrate GitLab with ArgoCD (GitOps)? Trigger Argo via webhook on image tag creation
45. What is pipeline efficiency score? GitLab metric showing wasted minutes due to long-running or failed jobs
46. How do you implement multi-project pipelines? Use trigger bridge jobs to orchestrate pipelines across repos
47. How do you use GitLab Pages with custom domain and HTTPS? Yes — add CNAME + GitLab auto-provisions Let’s Encrypt certificate
48. How do you debug a failed job locally? Use gitlab-runner exec docker job_name –docker-volumes
49. What is the difference between rules: and workflow: rules:? workflow: rules → controls if entire pipeline runs rules: → controls individual jobs
50. How do you implement zero-downtime deployments with Kubernetes? Use rolling update strategy + readiness/liveness probes + manual promotion job
51. How do you implement AI-powered test generation in 2025? GitLab Duo can suggest unit tests directly in MR
52. How do you implement license compliance checking?YAMLinclude: - template: Security/License-Scanning.gitlab-ci.yml
53. How do you handle large artifacts (videos, ML models)? Use external object storage (S3, GCS) with artifacts:s3
54. How do you implement shift-left security? Run SAST, secret detection, dependency scanning in every pipeline automatically
55. What is GitLab CI/CD Component Catalog (2025)? Reusable pipeline components (like reusable workflows) stored in catalog
56. How do you implement database rollback in GitLab? Manual job with –down migrations or blue-green DB switch
57. What is GitLab Runner Fleet Dashboard? Centralized view of all runners, health, usage across projects
58. How do you implement cost optimization for runners? Use interruptible + autoscaling + spot instances
59. How do you implement compliance as code? Use required pipeline templates at root group level
60. What is the most powerful GitLab CI feature in 2025? AI-native DevSecOps with Duo + full lifecycle traceability in one platform

Master these 60+ questions, and you will confidently clear any GitLab CI/CD interview in 2025 — from startups to Fortune 100 companies.

Need GitLab migration, pipeline optimization, or enterprise DevSecOps consulting? CloudSoftSol is a verified GitLab Professional Services Partner helping global teams achieve 10x faster delivery.

Start automating smarter today with CloudSoftSol!