CI/CD Fundamentals

Learning objectives#

• Define CI, continuous delivery and continuous deployment
• Describe pipeline stages
• Explain build once, deploy many
• Add quality gates

Explanation#

Continuous integration (CI): every change is merged often and automatically built and tested.

Continuous delivery: every passing build is releasable; a person approves production. Continuous deployment: it goes to production automatically.

Build once, deploy many: create one artifact (zip or container image) and promote the same artifact through dev, staging and production.

Quality gates stop the pipeline: failed tests, low coverage, security findings or a failed staging smoke test.

Code example: A typical pipeline#

1┌────────── CI (every PR) ──────────┐   ┌──────────── CD (main) ─────────────┐
2 checkout → restore → build → test →     build image → push v1.4.0 → deploy staging
3 lint → security scan → ✔ checks         → smoke test → approval → deploy prod
4                                          (same image v1.4.0 in every environment)

Broken code never merges; the exact image tested in staging is the one released to production.

This example is illustrative. Copy or download it and run it in your own environment; the expected output is shown above.

Step-by-step explanation#

1. CI runs on every pull request.
2. Merging to main starts CD.
3. One versioned artifact is promoted through environments.
4. Gates and approvals protect production.

Real-world use case#

Common mistakes#

Best practices#

• Keep CI under ~10 minutes
• Build once, promote the same artifact
• Configuration via environment variables
• Automate rollback

Remember this#

Practice exercise#

1Continuous delivery.

Mini quiz#

Want more? Practise all DevOps MCQs · DevOps interview questions

Related topics#

My notes#

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