What is GitHub Actions and how does CI/CD work
CI/CD definition, GitHub Actions overview, automation pipeline concept, event-driven workflows, software delivery lifecycle
What is CI/CD?
CI/CD stands for Continuous Integration and Continuous Delivery. CI means every code push is automatically built and tested. CD means passing builds are automatically deployed to an environment — staging or production.
Without CI/CD, teams integrate code manually, discover bugs late, and deploy infrequently. With CI/CD, integration happens on every commit, feedback is instant, and deployment is a non-event.
Where GitHub Actions Fits
GitHub Actions is GitHub's built-in CI/CD platform. You define automation logic as YAML files stored in your repository under .github/workflows/. GitHub executes these workflows on its cloud infrastructure — no separate CI server needed.
Actions are event-driven. An event (like a push) triggers a workflow. The workflow runs one or more jobs. Each job runs on a runner (a virtual machine) and executes a sequence of steps.
Key Terms
Workflow — a YAML file defining automated processes. Event — what triggers the workflow (push, pull request, schedule). Job — a group of steps running on one runner. Step — a single shell command or reusable Action. Runner — the VM that executes the job (Ubuntu, Windows, or macOS).
GitHub provides hosted runners free for public repositories and with usage limits on private ones. You can also self-host runners on your own infrastructure.