🚀 Linux Caching System

A high-performance, secure caching infrastructure for APT packages in Debian-based environments

Developed as part of my thesis project at the University of Bologna (2023/2024), this system optimizes package management in corporate environments through intelligent caching and secure VPN connectivity.

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📋 Table of Contents

• Overview
• Key Features
• Architecture
• Technologies
• Getting Started
• Configuration
• Results
• Contributing
• License
• Author

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🎯 Overview

In modern corporate environments, managing software packages across multiple machines can be challenging. Repeatedly downloading the same packages from remote repositories leads to:

• ⚠️ Excessive bandwidth consumption
• 🐌 Slow download speeds
• 💸 Increased operational costs
• 🔄 Network congestion

This project addresses these challenges by implementing a centralized caching proxy that stores downloaded packages locally and serves them to multiple clients through a secure VPN tunnel.

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✨ Key Features

🎯 Performance

• Smart Caching: First download caches the package; subsequent requests served instantly
• Bandwidth Optimization: Reduces redundant downloads by up to 80%
• Speed Improvement: Significantly faster package installation across the network

🔒 Security

• WireGuard VPN: Modern, lightweight VPN with state-of-the-art cryptography
• Encrypted Communications: All traffic between clients and server is protected
• Network Isolation: Secure tunnel prevents unauthorized access

🛠️ Infrastructure

• Automated Deployment: Complete setup via Vagrant provisioning scripts
• Reproducible Environments: Consistent configuration across all instances
• Scalable Architecture: Easy to add new clients to the network

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🏗️ Architecture

┌─────────────────────────────────────────────────────────┐
│                    Corporate Network                    │
│                                                         │
│  ┌──────────────┐         ┌──────────────┐            │
│  │   Client 1   │         │   Client 2   │            │
│  │  (Ubuntu)    │         │  (Ubuntu)    │            │
│  └──────┬───────┘         └──────┬───────┘            │
│         │                        │                     │
│         │   WireGuard VPN        │                     │
│         └────────┬───────────────┘                     │
│                  │                                      │
│         ┌────────▼─────────┐                           │
│         │  Cache Server    │                           │
│         │  apt-cacher-ng   │                           │
│         │  + WireGuard     │                           │
│         └────────┬─────────┘                           │
│                  │                                      │
└──────────────────┼─────────────────────────────────────┘
                   │
                   ▼
          Internet / APT Repositories

Component Overview

Component	Technology	Purpose
Virtualization	Vagrant + VirtualBox	Automated VM management
Cache Server	apt-cacher-ng	Package caching proxy
VPN	WireGuard	Secure client-server communication
OS	Ubuntu 18.04 (Bionic)	Base system for all machines

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💻 Technologies

Core Stack

• Vagrant - Infrastructure automation and VM management
• apt-cacher-ng - Specialized APT package caching proxy
• WireGuard - Fast, modern VPN implementation
• VirtualBox - Virtualization provider

Why These Technologies?

Vagrant over Docker/Multipass:

• Complete OS-level isolation
• Better network control for VPN configuration
• Easier filesystem management for caching
• Reproducible environments with simple configuration

apt-cacher-ng over Squid/Approx:

• Optimized specifically for APT packages
• Native support for package signatures and dependencies
• Automatic cache management
• Simpler configuration for Debian-based systems

WireGuard over OpenVPN/IPsec:

• Superior performance (lower latency, faster speeds)
• Modern cryptography
• Minimal configuration complexity
• Smaller codebase = reduced attack surface

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🚀 Getting Started

Prerequisites

Ensure you have the following installed:

• Vagrant (2.0+)
• VirtualBox (6.0+)
• Unix-based host system (Linux/macOS)

Installation

1. Clone the repository

   git clone https://github.com/yourusername/linux-package-caching.git
   cd linux-package-caching

2. Configure the environment

   Edit the Vagrantfile if you need to customize:

   • Number of clients
   • Network configuration
   • Resource allocation (RAM, CPU)

3. Deploy the infrastructure

   vagrant up

   This command will:

   • Create and configure the cache server
   • Set up WireGuard VPN
   • Deploy client VMs
   • Run all provisioning scripts automatically

4. Verify the setup

   vagrant status

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⚙️ Configuration

Server Configuration

The server is automatically configured via setup_apt_cacher.sh:

• apt-cacher-ng: Listens on VPN interface (10.0.0.1:3142)
• WireGuard: Creates secure tunnel on UDP port 51820
• Firewall: Configured with iptables for proper routing

Client Configuration

Clients are provisioned using setup_client.sh:

# APT proxy configuration is automatically set to:
Acquire::http::Proxy "http://10.0.0.1:3142";

Adding New Clients

To connect external Debian-based machines:

1. Copy the client setup script

   scp setup_client.sh user@external-machine:~/

2. Update the server endpoint in the script:

   SERVER_ENDPOINT="<server-ip>:51820"

3. Run the setup

   chmod +x setup_client.sh
   ./setup_client.sh

4. Add peer to server (/etc/wireguard/wg0.conf):

   [Peer]
   PublicKey = <client-public-key>
   AllowedIPs = 10.0.0.X/32

5. Restart WireGuard on server:

   sudo wg-quick down wg0
   sudo wg-quick up wg0

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📊 Results

The implementation demonstrated significant improvements:

Performance Metrics

• ✅ Bandwidth Reduction: ~80% decrease in external bandwidth usage
• ✅ Speed Improvement: 3-5x faster package installation for cached packages
• ✅ Network Efficiency: Reduced load on upstream repositories

Security

• 🔒 All client-server communications encrypted via WireGuard
• 🔒 Zero-trust network architecture
• 🔒 Protected against man-in-the-middle attacks

Operational Benefits

• 🔄 Fully automated deployment and configuration
• 📦 Reproducible infrastructure as code
• 🎯 Easy scalability for additional clients

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🧪 Testing

Test with Vagrant Clients

1. SSH into a client

   vagrant ssh client-1

2. Update package lists

   sudo apt update

3. Install a package

   sudo apt install -y htop

4. Verify caching (install same package on client-2 - should be much faster)

   vagrant ssh client-2
   sudo apt install -y htop

Monitor Cache Performance

Access the apt-cacher-ng web interface:

http://10.0.0.1:3142/acng-report.html

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🤝 Contributing

Contributions are welcome! Here's how you can help:

1. Fork the repository
2. Create a feature branch (git checkout -b feature/AmazingFeature)
3. Commit your changes (git commit -m 'Add some AmazingFeature')
4. Push to the branch (git push origin feature/AmazingFeature)
5. Open a Pull Request

Ideas for Contributions

• Support for additional Linux distributions (Fedora, CentOS)
• Docker-based implementation
• Monitoring and metrics dashboard
• Automated testing suite
• Cloud deployment guides (AWS, Azure, GCP)

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📝 License

This project is licensed under the MIT License - see the LICENSE file for details.

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👨‍💻 Author

Samite Mounir

Bachelor's Thesis in Computer Science and Engineering
Alma Mater Studiorum - Università di Bologna
Academic Year 2023/2024

Advisor: Prof. Vittorio Ghini

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🙏 Acknowledgments

Special thanks to:

• Prof. Vittorio Ghini for supervision and guidance
• The University of Bologna, School of Engineering
• The open-source community behind Vagrant, WireGuard, and apt-cacher-ng

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📚 Additional Resources

• Official Thesis Publication
• apt-cacher-ng Documentation
• WireGuard Documentation
• Vagrant Documentation

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