GitHub Actions Tutorial — GitHub-Hosted Runners
GitHub-Hosted Runners
GitHub provides free virtual machines (runners) that execute your workflow jobs. Each job gets a fresh, clean VM — nothing persists between jobs or workflow runs.
Available Runners
| Label | OS | Architecture |
|---|---|---|
ubuntu-latest |
Ubuntu 22.04 | x64 |
ubuntu-24.04 |
Ubuntu 24.04 | x64 |
ubuntu-22.04 |
Ubuntu 22.04 | x64 |
windows-latest |
Windows Server 2022 | x64 |
windows-2022 |
Windows Server 2022 | x64 |
macos-latest |
macOS 14 (Sonoma) | arm64 (M1) |
macos-14 |
macOS 14 (Sonoma) | arm64 (M1) |
macos-13 |
macOS 13 (Ventura) | x64 (Intel) |
Tip: ubuntu-latest is the most common choice. It’s the cheapest (1× minute multiplier), has the most pre-installed tools, and starts the fastest.
Hardware Specs
| Runner | CPUs | RAM | Storage |
|---|---|---|---|
| Linux | 4 vCPUs | 16 GB | 14 GB SSD |
| Windows | 4 vCPUs | 16 GB | 14 GB SSD |
| macOS | 3 vCPUs (M1) | 7 GB | 14 GB SSD |
Pre-Installed Software
GitHub-hosted runners come with a rich set of pre-installed tools:
Ubuntu Runner
| Category | Tools |
|---|---|
| Languages | Node.js 18/20, Python 3.10/3.12, Java 11/17/21, Go, Ruby, Rust, .NET |
| Package Managers | npm, yarn, pip, Maven, Gradle, NuGet, Cargo |
| Build Tools | gcc, g++, make, cmake |
| Containers | Docker, Docker Compose |
| CLIs | aws, az, gcloud, kubectl, helm, terraform |
| Databases | PostgreSQL, MySQL (installed, not running) |
| Browsers | Chrome, Firefox (for UI testing) |
The full list of installed software is published at: github.com/actions/runner-images
Choosing the Right Runner
| Use Case | Recommended Runner |
|---|---|
| General CI (build, test, lint) | ubuntu-latest |
| iOS/macOS app builds | macos-latest |
| Windows-specific builds (.NET, PowerShell) | windows-latest |
| Cross-platform testing | Matrix of all three |
| Cost optimization | ubuntu-latest (cheapest) |
Cost Comparison
| Runner | Minute Multiplier |
|---|---|
ubuntu-latest |
1× |
windows-latest |
2× |
macos-latest |
10× |
A 10-minute job costs 10 Linux minutes, 20 Windows minutes, or 100 macOS minutes.
Runner Environment Details
Every job starts with a clean VM. Here’s what’s available:
jobs:
info:
runs-on: ubuntu-latest
steps:
- name: Runner details
run: |
echo "OS: $RUNNER_OS"
echo "Arch: $RUNNER_ARCH"
echo "Name: $RUNNER_NAME"
echo "Temp: $RUNNER_TEMP"
echo "Workspace: $GITHUB_WORKSPACE"
echo "Home: $HOME"
Expected output:
OS: Linux
Arch: X64
Name: GitHub Actions 42
Temp: /home/runner/work/_temp
Workspace: /home/runner/work/repo-name/repo-name
Home: /home/runner
Larger Runners (GitHub Teams/Enterprise)
GitHub offers larger runner sizes for paid plans:
| Size | CPUs | RAM | Multiplier |
|---|---|---|---|
| Standard | 4 | 16 GB | 1× |
| 8-core | 8 | 32 GB | 2× |
| 16-core | 16 | 64 GB | 4× |
| 32-core | 32 | 128 GB | 8× |
| 64-core | 64 | 256 GB | 16× |
Larger runners are configured in your organization settings, not in the YAML file.
Quick Reference
| Property | Value |
|---|---|
| Default runner | ubuntu-latest |
| Fresh VM per job | Yes — no state between jobs |
| Pre-installed tools | Node, Python, Java, Docker, cloud CLIs |
| Disk space | ~14 GB SSD |
| Job timeout | 6 hours max |
| Cheapest option | Linux (1× multiplier) |
← Previous: Defining Jobs
Next: Job Dependencies →
