Split tutorial into separate automatic and manual guides

- Remove combined CREATE_APPLIANCE_TUTORIAL.md
- Add AUTOMATIC_APPLIANCE_GUIDE.md (5 min quick start)
- Add MANUAL_APPLIANCE_GUIDE.md (full control, 30-45 min)
- Add docs/README.md with guide comparison and selection help

Benefits:
- Clearer separation of concerns
- Easier to navigate and find relevant information
- Better for beginners (automatic guide is simpler)
- Better for advanced users (manual guide has full details)
- Comparison table helps users choose the right approach

Author: OpenNebula Community Contributor

docs/AUTOMATIC_APPLIANCE_GUIDE.md

@@ -0,0 +1,367 @@
+# Creating OpenNebula Appliances - Automatic Method
+
+**Quick appliance creation using the generator script (5 minutes)**
+
+---
+
+## 📖 Introduction
+
+This guide shows you how to quickly create OpenNebula appliances from Docker containers using an automated generator script. The generator creates all necessary files following the proven Phoenix RTOS/Node-RED structure.
+
+**What you'll create:**
+- A VM image (QCOW2 format) with Ubuntu 22.04 + Docker
+- Automatic Docker container startup on VM boot
+- SSH access with password and key authentication
+- Console and serial console auto-login
+- OpenNebula context integration for runtime configuration
+
+**Time required:** ~5 minutes for generation + 15-20 minutes for building
+
+---
+
+## ✅ Prerequisites
+
+- Linux system (Ubuntu 22.04+ recommended)
+- Git
+- Packer (for building the image)
+- QEMU/KVM (for building the image)
+
+```bash
+sudo apt update
+sudo apt install -y git qemu-kvm qemu-utils
+```
+
+---
+
+## 🚀 Quick Start
+
+### Step 1: Clone Repository
+
+```bash
+git clone https://github.com/OpenNebula/marketplace-community.git
+cd marketplace-community
+```
+
+### Step 2: Create Configuration File
+
+Create a `.env` file with your Docker container details:
+
+```bash
+cd docs/automatic-appliance-tutorial
+
+cat > myapp.env << 'ENVEOF'
+# Required variables
+DOCKER_IMAGE="your-docker-image:tag"
+APPLIANCE_NAME="myapp"
+APP_NAME="MyApp"
+PUBLISHER_NAME="Your Name"
+PUBLISHER_EMAIL="your.email@example.com"
+
+# Optional variables
+APP_DESCRIPTION="MyApp description"
+APP_FEATURES="Feature 1,Feature 2,Feature 3"
+DEFAULT_CONTAINER_NAME="myapp-container"
+DEFAULT_PORTS="8080:8080"
+DEFAULT_ENV_VARS=""
+DEFAULT_VOLUMES="/data:/data"
+APP_PORT="8080"
+WEB_INTERFACE="true"
+ENVEOF
+```
+
+### Step 3: Run Generator
+
+```bash
+./generate-docker-appliance.sh myapp.env
+```
+
+The generator will:
+1. Create all appliance files
+2. Generate Packer configuration
+3. Prompt you to build the image immediately
+
+**Output:**
+```
+🚀 Loading configuration from myapp.env
+🎯 Generating complete appliance: myapp (MyApp)
+📁 Creating directory structure...
+✅ Directory structure created
+📝 Generating metadata.yaml...
+✅ Metadata files generated
+📝 Generating README.md...
+✅ README.md generated
+📝 Generating appliance.sh installation script...
+✅ appliance.sh generated
+📝 Generating Packer configuration files...
+✅ Packer configuration files generated
+🎉 Appliance 'myapp' generated successfully!
+
+Do you want to build the image now? (y/n):
+```
+
+### Step 4: Build the Image
+
+If you answered 'y' to the prompt, the build starts automatically. Otherwise:
+
+```bash
+cd ../../apps-code/community-apps
+make myapp
+```
+
+**Build time:** 15-20 minutes (downloads Ubuntu, installs Docker, pulls your container image)
+
+**Output file:** `export/myapp.qcow2`
+
+---
+
+## 📋 Configuration Variables
+
+| Variable | Required | Description | Example |
+|----------|----------|-------------|---------|
+| `DOCKER_IMAGE` | Yes | Docker image name | `nginx:alpine` |
+| `APPLIANCE_NAME` | Yes | Lowercase name (no spaces) | `nginx` |
+| `APP_NAME` | Yes | Display name | `NGINX Web Server` |
+| `PUBLISHER_NAME` | Yes | Your name | `John Doe` |
+| `PUBLISHER_EMAIL` | Yes | Your email | `john@example.com` |
+| `APP_DESCRIPTION` | No | Full description | `NGINX is a web server...` |
+| `APP_FEATURES` | No | Comma-separated features | `Web Server,Reverse Proxy` |
+| `DEFAULT_CONTAINER_NAME` | No | Container name | `nginx-container` |
+| `DEFAULT_PORTS` | No | Port mappings | `80:80,443:443` |
+| `DEFAULT_ENV_VARS` | No | Environment variables | `KEY=value,KEY2=value2` |
+| `DEFAULT_VOLUMES` | No | Volume mappings | `/data:/data,/config:/config` |
+| `APP_PORT` | No | Main application port | `80` |
+| `WEB_INTERFACE` | No | Has web UI? | `true` or `false` |
+
+---
+
+## 📁 Generated Files
+
+The generator creates:
+
+```
+marketplace-community/
+├── appliances/myapp/
+│   ├── appliance.sh          # Installation script
+│   ├── metadata.yaml         # Build configuration
+│   ├── <uuid>.yaml          # Marketplace metadata
+│   ├── README.md            # Documentation
+│   ├── CHANGELOG.md         # Version history
+│   └── tests/
+│       └── tests.yaml       # Test configuration
+└── apps-code/community-apps/packer/myapp/
+    ├── myapp.pkr.hcl        # Packer build file
+    └── myapp.auto.pkrvars.hcl  # Packer variables
+```
+
+---
+
+## 🔧 Customization
+
+After generation, you can customize the files:
+
+### Modify Container Configuration
+
+Edit `appliances/myapp/appliance.sh`:
+
+```bash
+# Change default values
+DEFAULT_CONTAINER_NAME="custom-name"
+DEFAULT_PORTS="8080:8080,8443:8443"
+DEFAULT_ENV_VARS="DEBUG=true,LOG_LEVEL=info"
+```
+
+### Add Custom Installation Steps
+
+Add to the `service_install()` function in `appliance.sh`:
+
+```bash
+service_install()
+{
+    # ... existing Docker installation ...
+    
+    # Add your custom steps here
+    apt-get install -y additional-package
+    
+    # Custom configuration
+    echo "custom config" > /etc/myapp.conf
+}
+```
+
+### Rebuild After Changes
+
+```bash
+cd apps-code/community-apps
+make clean
+make myapp
+```
+
+---
+
+## 📦 Examples
+
+See `docs/automatic-appliance-tutorial/examples/` for complete working examples:
+
+### NGINX Web Server
+
+```bash
+cat > nginx.env << 'EOF'
+DOCKER_IMAGE="nginx:alpine"
+APPLIANCE_NAME="nginx"
+APP_NAME="NGINX"
+PUBLISHER_NAME="Your Name"
+PUBLISHER_EMAIL="your@email.com"
+DEFAULT_PORTS="80:80,443:443"
+APP_PORT="80"
+WEB_INTERFACE="true"
+EOF
+
+./generate-docker-appliance.sh nginx.env
+```
+
+### Node-RED
+
+```bash
+cat > nodered.env << 'EOF'
+DOCKER_IMAGE="nodered/node-red:latest"
+APPLIANCE_NAME="nodered"
+APP_NAME="Node-RED"
+PUBLISHER_NAME="Your Name"
+PUBLISHER_EMAIL="your@email.com"
+DEFAULT_PORTS="1880:1880"
+DEFAULT_VOLUMES="/data:/data"
+APP_PORT="1880"
+WEB_INTERFACE="true"
+EOF
+
+./generate-docker-appliance.sh nodered.env
+```
+
+### PostgreSQL Database
+
+```bash
+cat > postgres.env << 'EOF'
+DOCKER_IMAGE="postgres:16-alpine"
+APPLIANCE_NAME="postgres"
+APP_NAME="PostgreSQL"
+PUBLISHER_NAME="Your Name"
+PUBLISHER_EMAIL="your@email.com"
+DEFAULT_PORTS="5432:5432"
+DEFAULT_ENV_VARS="POSTGRES_PASSWORD=changeme"
+DEFAULT_VOLUMES="/var/lib/postgresql/data:/var/lib/postgresql/data"
+APP_PORT="5432"
+WEB_INTERFACE="false"
+EOF
+
+./generate-docker-appliance.sh postgres.env
+```
+
+---
+
+## 🧪 Testing Your Appliance
+
+### 1. Test Locally with QEMU
+
+```bash
+cd apps-code/community-apps/export
+
+# Start VM with QEMU
+qemu-system-x86_64 \
+  -enable-kvm \
+  -m 2048 \
+  -smp 2 \
+  -drive file=myapp.qcow2,format=qcow2 \
+  -net nic -net user,hostfwd=tcp::2222-:22,hostfwd=tcp::8080-:8080 \
+  -vnc :0
+```
+
+Connect via VNC to `localhost:5900` and verify:
+- Console auto-login works
+- Docker container is running: `docker ps`
+- Application is accessible
+
+### 2. Test on OpenNebula
+
+See the [Manual Appliance Guide](MANUAL_APPLIANCE_GUIDE.md#deploying-to-opennebula) for detailed deployment instructions.
+
+---
+
+## 🐛 Troubleshooting
+
+### Generator Fails
+
+**Problem:** Missing required variables  
+**Solution:** Check all required variables are set in .env file
+
+```bash
+# Verify your .env file has all required fields
+grep -E "DOCKER_IMAGE|APPLIANCE_NAME|APP_NAME|PUBLISHER" myapp.env
+```
+
+### Build Fails
+
+**Problem:** Packer build fails  
+**Solution:** Check Packer logs
+
+```bash
+cd apps-code/community-apps
+make myapp 2>&1 | tee build.log
+```
+
+Common issues:
+- Network connectivity (can't download Ubuntu ISO)
+- Insufficient disk space
+- Docker image doesn't exist or is private
+
+### Container Doesn't Start
+
+**Problem:** Container fails to start on VM boot  
+**Solution:** Check the generated `appliance.sh` for correct Docker image name
+
+```bash
+# Verify Docker image name in appliance.sh
+grep "DOCKER_IMAGE=" appliances/myapp/appliance.sh
+```
+
+### Permission Issues
+
+**Problem:** Container can't write to volumes  
+**Solution:** The generator automatically sets ownership to `1000:1000`. If your container uses a different UID, edit `appliance.sh`:
+
+```bash
+# In service_install() function
+mkdir -p /data
+chown 1001:1001 /data  # Change to your container's UID:GID
+```
+
+---
+
+## 📤 Next Steps
+
+After successfully building and testing your appliance:
+
+1. **Add a logo** - Create a 256x256 PNG logo at `logos/myapp.png`
+2. **Test thoroughly** - Deploy on OpenNebula and verify all functionality
+3. **Submit to marketplace** - See [Manual Appliance Guide](MANUAL_APPLIANCE_GUIDE.md#submitting-to-marketplace) for PR instructions
+
+---
+
+## 💡 Tips
+
+- **Start simple** - Begin with minimal configuration, add features incrementally
+- **Use official images** - Prefer official Docker images from Docker Hub
+- **Test the Docker image first** - Run `docker run` locally before generating appliance
+- **Check examples** - Study the example .env files for reference
+- **Volume permissions** - If container runs as non-root, ensure volume directories have correct ownership
+- **Environment variables** - Use DEFAULT_ENV_VARS for container configuration
+- **Port conflicts** - Ensure ports don't conflict with system services
+
+---
+
+## 📖 Additional Resources
+
+- [Manual Appliance Guide](MANUAL_APPLIANCE_GUIDE.md) - For advanced customization
+- [OpenNebula Documentation](https://docs.opennebula.io/)
+- [Docker Hub](https://hub.docker.com/)
+- [Packer Documentation](https://www.packer.io/docs)
+- [OpenNebula Marketplace](https://marketplace.opennebula.io/)
+