Github Actions Basics

Get a concise introduction to GitHub Actions — an integrated automation platform for repositories hosted on GitHub. If your code already lives on GitHub, Actions offers a seamless way to build CI/CD pipelines, run repository automations, and respond to events without adopting an external CI system. What is GitHub Actions? GitHub Actions is a flexible automation platform built into GitHub. You define automated processes as workflows using YAML files stored in your repository, and GitHub executes those workflows in response to repository events. With Actions you can:

Build, test, and deploy code on pushes and pull requests.
Run checks and analyses (linting, security scans, dependency updates).
Orchestrate repository automations (comment bots, labeling, notifications).
Schedule workflows or trigger them from webhooks and other GitHub events.

Workflows and jobs can run on multiple operating systems, including Ubuntu, Windows, and macOS.

Why choose GitHub Actions?

Hosted infrastructure managed by GitHub (provisioning, scaling, and maintenance).
Declarative workflows in YAML that live with your code (.github/workflows/).
Built-in capabilities: dependency caching, artifact storage, and detailed logs.
Automation reduces manual steps, lowers human error, and accelerates delivery.

Is GitHub Actions only for CI/CD pipelines? No. CI/CD (build, test, release) is a primary use case, but Actions can run workflows on many repository events — pushes, pull requests, issues, package registry events, and more. For example, when a contributor opens a pull request you can automatically add labels, assign reviewers, post comments, or run security scans.

Core concepts: workflows, jobs, steps, and runners

Workflow: an automated process defined in a YAML file stored in /.github/workflows/. A repository can contain multiple workflows triggered by different events.
Job: a group of steps that runs on a single runner. Jobs run in parallel by default unless you specify dependencies with needs.
Step: a single task in a job. Steps run sequentially within a job.
Runner: the machine (virtual or physical) that executes a job. Runners are either GitHub-hosted or self-hosted.

Quick reference table

Concept	Purpose	Example
Workflow	Defines automation and triggers	`/.github/workflows/ci.yml`
Job	Group of steps that run on one runner	`jobs: build:`
Step	Single task (action or command)	`- name: Install dependencies`
Runner	Execution environment	`runs-on: ubuntu-latest`

Matrix strategy and parallel jobs A common pattern uses a matrix strategy to run the same job across multiple OSes or versions. Each matrix entry becomes a separate job executed concurrently on its own runner. Example: run tests on Ubuntu, macOS, and Windows

name: My Awesome App
on: push
jobs:
  unit-testing:
    name: Unit Testing
    strategy:
      matrix:
        os: [ubuntu-latest, macos-latest, windows-latest]
        node-version: [16]
    runs-on: ${{ matrix.os }}
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Set up Node.js ${{ matrix.node-version }}
        uses: actions/setup-node@v3
        with:
          node-version: ${{ matrix.node-version }}

      - name: Install dependencies
        run: npm ci

      - name: Run tests
        run: npm test

Execution notes

GitHub provisions a separate runner for each matrix job concurrently (three runners in the example).
Steps inside a job execute sequentially (checkout → setup → install → test).
Each matrix job is evaluated independently: a matrix instance’s success or failure is reported separately. The overall workflow succeeds only when all required jobs complete successfully.
You can view logs, step output, and artifacts for each job in the repository’s Actions tab.

A screenshot of a GitHub Actions run on the left showing jobs and detailed unit-testing steps, and on the right three colored diagrams of GitHub-hosted runners (Windows, Ubuntu, macOS) each performing "Clone Repo," "Install NodeJS," and "Run Tests."

Runner types — GitHub-hosted vs. self-hosted There are two main runner options:

Runner type	Pros	Cons	When to use
GitHub-hosted	No server maintenance; fresh environment per job; common tooling preinstalled	Limited control over system-level config; usage subject to GitHub plan limits	Best for typical CI/CD where convenience and low ops overhead matter
Self-hosted	Full control over OS, installed software, and network access; can access private resources or GPUs	You manage maintenance, scaling, and security	Use when you need custom software, specific hardware, or private network access

Choose GitHub-hosted runners for convenience and low maintenance. Choose self-hosted runners when you need custom software, special hardware, or specific network access that hosted runners can’t provide.

An infographic titled "Runner Types" that compares GitHub-hosted Runners (green) and Self-hosted Runners (orange) with icons and bullet-pointed features and trade-offs. The bottom shows colored buttons for Workflow, Jobs, Steps, and Runners.

Summary and next steps This article covered the essentials of GitHub Actions: what it is, how workflows, jobs, steps, and runners relate, how matrix jobs enable parallel runs across OSes, and the differences between GitHub-hosted and self-hosted runners. Use these fundamentals to design CI/CD workflows and repository automations. Further reading and references

GitHub Actions docs: https://docs.github.com/actions
Actions marketplace: https://github.com/marketplace?type=actions
actions/checkout: https://github.com/actions/checkout
actions/setup-node: https://github.com/actions/setup-node

Shared Libraries in Jenkins

Agents and Nodes in Jenkins

Pipeline Enhancement and Caching

Pipeline Structure and Scripted vs Declarative

Jenkins Administration and Monitoring

Backup and Configuration Management

Introduction

Github Actions Basics

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