CI/CD Pipelines

Concept of the skill

A CI/CD pipeline is the automated path a change travels from commit to released artifact. It is modeled as a directed graph of stages, each stage a gate the change must pass, ordered so the cheapest and fastest gates run first and the most expensive last. The pipeline's job is to make integration continuous (every commit proves it merges and passes tests against a shared mainline) and release boring (a single build-once artifact is always in a releasable state and can be promoted through environments on demand).

Three terms are routinely conflated and must stay distinct:

• Continuous Integration (CI): every commit to a shared mainline is automatically built and verified by a self-testing build. The point is to catch integration failures within minutes of the commit that caused them.
• Continuous Delivery (CD): the codebase is always in a deployable state; a verified artifact is produced and can be released to production at the push of a button (a human approval may gate the final step).
• Continuous Deployment: the same as continuous delivery, but the final release step is automatic too — every change that passes all gates goes to production with no human gate.

Coverage

This skill covers the design and operation of the pipeline itself: