CI vs CD and the pipeline

Continuous Integration (CI) means every commit is automatically built and tested against the shared mainline, many times a day, so integration problems surface in minutes instead of at a big merge. Continuous Delivery (CD) means every green build is automatically prepared into a deployable artifact and can be released with one click; Continuous Deployment goes further and ships every green build to production with no human gate.

• CI: build + unit/integration tests on every push; fast feedback, keep the mainline green.
• Continuous Delivery: any commit that passes is releasable, but a human chooses when to push the button.
• Continuous Deployment: no button — every passing commit goes to prod automatically.
• The shared goal: shrink the batch size and the feedback loop so failures are small and cheap to fix.

# A minimal pipeline (any CI system)
stages:
  - build      # compile / package, produce an immutable artifact
  - test       # unit, integration, lint, security scan
  - publish    # push image to a registry, tag by commit SHA
  - deploy     # roll out to staging, then prod (gated or automatic)