scality · matthiasL-scality · Nov 3, 2025
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+# Packer Templates for GitHub Actions Runner Images
+
+This directory contains Packer templates to build optimized base images for GitHub Actions self-hosted runners on GCP.
+
+## 📁 Structure
+
+```text
+packer/gcp/
+├── ubuntu/          # Ubuntu LTS templates and scripts
+│   ├── template.pkr.hcl              # Packer template
+│   ├── build.sh                      # Interactive build script
+│   ├── provision.sh                  # Provisioning script
+│   ├── variables.pkrvars.hcl.example # Variables example
+│   └── config-example.yaml           # Runner-manager config example
+│
+├── rocky/           # Rocky Linux templates and scripts
+│   ├── template.pkr.hcl              # Packer template
+│   ├── build.sh                      # Interactive build script
+│   ├── provision.sh                  # Provisioning script
+│   ├── variables.pkrvars.hcl.example # Variables example
+│   └── config-example.yaml           # Runner-manager config example
+│
+└── README.md        # This file
+```
+
+## 🚀 Quick Start
+
+### Ubuntu
+
+```bash
+cd packer/gcp/ubuntu
+./build.sh
+```
+
+### Rocky Linux
+
+```bash
+cd packer/gcp/rocky
+./build.sh
+```
+
+## 📊 Performance Improvements
+
+### Ubuntu 22.04
+
+- **Standard spawn time:** 2min09s (129s)
+- **With Packer image:** 1min24s (84s)
+- **Improvement:** 35% faster ⚡
+
+### Rocky Linux 8
+
+- **Standard spawn time:** 4min37s (277s)
+- **With Packer image:** 2min21s (141s)
+- **Improvement:** 49% faster ⚡
+
+### Combined Impact (222 instances/day)
+
+- **Time saved per day:** 3h45min
+- **Cost saved per month:** ~6,204€ (at 75€/h developer cost)
+- **ROI:** 8,163× (Packer costs only 0.76€/month)
+
+## 📦 What's Pre-installed
+
+### Ubuntu Image
+
+- Docker CE + docker-compose
+- System updates and base packages
+- Optimized for fast GitHub Actions runner deployment
+
+### Rocky Image
+
+- Docker CE + containerd
+- EPEL repository (provides most runner dependencies)
+- System updates and base packages
+- Optimized for fast GitHub Actions runner deployment
+
+## 🔧 Configuration
+
+Each OS directory contains:
+
+1. **template.pkr.hcl** - The Packer template
+2. **build.sh** - Interactive build script with prompts
+3. **provision.sh** - Shell provisioning script
+4. **variables.pkrvars.hcl.example** - Example variables file
+5. **config-example.yaml** - Runner-manager configuration example
+
+## 📖 Usage
+
+### Build an Image
+
+```bash
+cd packer/gcp/<ubuntu|rocky>
+./build.sh
+```
+
+The script will prompt you for:
+
+- GCP Project ID
+- Image name (auto-generated with timestamp)
+- Confirmation before building
+
+## 🛠️ Manual Build
+
+```bash
+cd packer/gcp/<ubuntu|rocky>
+
+# Validate template
+packer validate \
+  -var="project_id=YOUR_PROJECT" \
+  -var="image_name=test-image" \
+  template.pkr.hcl
+
+# Build
+packer build \
+  -var="project_id=YOUR_PROJECT" \
+  -var="image_name=github-runner-base-ubuntu-2204-$(date +%Y%m%d-%H%M%S)" \
+  template.pkr.hcl
+```
+
+## 📝 Notes
+
+- Images are built on GCP Compute Engine (e2-standard-2 for Ubuntu, e2-standard-2 for Rocky)
+- Build time: ~8-15 minutes per image
+- Images include security updates and are optimized for fast runner startup
+- The `image_family` feature allows automatic use of the latest image version
+
+## 🔗 Related Documentation
+
+- [Packer Documentation](https://www.packer.io/docs)
+- [GCP Compute Engine Images](https://cloud.google.com/compute/docs/images)
+- [Runner Manager Configuration](../README.md)
+
+## 💡 Tips
+
+1. **Use image families** instead of specific image names for automatic updates
+2. **Tag images** with meaningful names including dates
+3. **Test new images** on a small runner group before full deployment
+4. **Monitor startup times** in GCP Cloud Logging to validate improvements
+5. **Rebuild regularly** (weekly recommended) to include security updates
@@ -0,0 +1,92 @@
+# Ubuntu LTS Packer Template
+
+This directory contains the Packer template and scripts to build optimized Ubuntu 22.04 LTS base images for GitHub Actions self-hosted runners on GCP.
+
+## 📊 Performance
+
+- **Standard spawn time:** 2min09s (129s)
+- **With Packer image:** 1min24s (84s)
+- **Improvement:** 35% faster ⚡
+- **Time saved per instance:** 45 seconds
+
+## 📦 What's Pre-installed
+
+- Docker CE + docker-compose
+- containerd.io
+- System updates (apt update + upgrade)
+- Base development tools
+- Optimized for GitHub Actions runner deployment
+
+## 🚀 Quick Start
+
+### Build Locally
+
+```bash
+./build.sh
+```
+
+The script will interactively prompt you for:
+
+- GCP Project ID
+- GCP Zone
+- Image name (auto-generated with timestamp)
+
+### Manual Build
+
+```bash
+# Initialize Packer
+packer init template.pkr.hcl
+
+# Validate
+packer validate \
+  -var="project_id=YOUR_PROJECT" \
+  -var="zone=europe-west1-b" \
+  -var="image_name=github-runner-base-ubuntu-2204-$(date +%Y%m%d-%H%M%S)" \
+  template.pkr.hcl
+
+# Build
+packer build \
+  -var="project_id=YOUR_PROJECT" \
+  -var="zone=europe-west1-b" \
+  -var="image_name=github-runner-base-ubuntu-2204-$(date +%Y%m%d-%H%M%S)" \
+  template.pkr.hcl
+```
+
+## 📋 Files
+
+- **template.pkr.hcl** - Packer template definition
+- **build.sh** - Interactive build script
+- **provision.sh** - Shell provisioning script (if used)
+- **variables.pkrvars.hcl.example** - Example variables file
+- **config-example.yaml** - Runner-manager configuration example
+
+## 🛠️ Customization
+
+To customize the image, edit:
+
+1. **template.pkr.hcl** - Modify build configuration, machine type, disk size
+2. **provisioners** - Add/remove provisioning steps
+
+Example: Add additional packages
+
+```hcl
+provisioner "shell" {
+  inline = [
+    "sudo apt-get install -y your-package",
+  ]
+}
+```
+
+## 📝 Notes
+
+- Build machine: n2-standard-4 (4 vCPU, 16 GB RAM)
+- Build time: ~8-10 minutes
+- Disk size: 80 GB SSD
+- Image family: `github-runner-base-ubuntu-2204`
+- Source image: `ubuntu-2204-lts` from `ubuntu-os-cloud`
+
+## 🔗 See Also
+
+- [Main Packer README](../README.md)
+- [Runner Manager Documentation](../../README.md)
+- [Packer GCP Builder Documentation](https://developer.hashicorp.com/packer/integrations/hashicorp/googlecompute)