What is a CI/CD pipeline and what are the key stages you'd expect in one?

technical-conceptual · Junior level · cloud-devops-security

What the interviewer is really asking

Determine whether the candidate has a mental model of the software delivery lifecycle and where automation adds value.

What to say

• CI (Continuous Integration) automatically builds and tests every code commit; CD (Continuous Delivery/Deployment) extends that to produce a releasable artifact or push it all the way to production.
• Typical stages: source trigger → build/compile → unit tests → static analysis/linting → artifact publish → deploy to test environment → integration/E2E tests → manual approval gate (if CD not fully automated) → deploy to production.
• The goal is to surface failures as early and cheaply as possible — a failing unit test in CI is far cheaper than a bug in production.

What to avoid

• Treating CI and CD as synonymous — they're distinct concepts even if often paired.
• Describing it only as 'automatic deployment' without mentioning the test and build phases.
• Forgetting security scanning stages (SAST, dependency vulnerability checks) which are increasingly standard.

Example answers

Strong: In a GitHub Actions workflow I set up: on every PR, the pipeline ran npm test, then eslint, then built a Docker image and ran Trivy for CVE scanning. Only on merge to main did it push to ECR and deploy to a staging ECS cluster.

Weak: CI/CD means every time you push code it automatically goes to production.