Overlay Lab

A platform for isolated programming exercises using Docker containers and a secure VXLAN overlay network.

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Table of Contents

1. Project Overview
2. Installation Guide
3. Usage Instructions
4. Key Features
5. Configuration
6. Contributing Guidelines
7. Visual Enhancements
8. Additional Resources

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Project Overview

Overlay Lab provides an environment where students complete programming exercises in isolated Docker containers connected via a secure VXLAN overlay network.

Core Goals:

• Isolation: Containerized exercises prevent interference between users
• Security: VXLAN network encrypts inter-container communication
• Flexibility: JSON-configurable exercises for client/server challenges

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Installation Guide

Prerequisites

• Docker
• Multipass
• NGINX

Setup Steps

1. Clone the repository:

   git clone https://github.com/AhmedHosny2/testbed-distributed-system.git
   cd projectname

2. Install dependencies (Ubuntu example):

   sudo apt update && sudo apt install docker.io multipass nginx

3. Launch the agent VM:

   multipass launch -n agent --cloud-init https://ovl.st.hs-ulm.de:4001/conf/user-data-mp.yaml jammy
   multipass shell

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Usage Instructions

1. Register VM in Overlay Network:

   sudo vx register -o  # Register VM
   sudo vx start        # Start overlay service
   ping 10.1.0.2        # Test connectivity

2. Configure NGINX:

   curl -o init_nginx.sh https://ulm.ahmed-yehia.me/init_nginx && chmod +x init_nginx.sh && sudo ./init_nginx.sh
   curl -o update_srv_ip.sh https://ulm.ahmed-yehia.me/update_srv_ip && chmod +x update_srv_ip.sh && sudo ./update_srv_ip.sh

3. Finalize Setup:

   curl -o agent_vm_ulm.ps1 https://ulm.ahmed-yehia.me/download && pwsh -ExecutionPolicy Bypass -File ./agent_vm_ulm.ps1

4. Access the portal at:

   http://server.local
   

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Key Features

• Container Isolation: Dedicated Docker containers per exercise
• VXLAN Security: Encrypted overlay network layer
• NGINX Proxy: IP preservation, load balancing, and DNS resolution
• JSON Configuration: Define exercises with custom parameters

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Configuration

Example JSON exercise definition:

{
    "ExerciseName": "grpc-app",
    "ExerciseReqConnectionType": "grpc",
    "ExerciseTile": "gRPC Adventure",
    "ExerciseDescription": "Dive into the world of gRPC! Build a client that connects to a gRPC server and interacts with it to create, fetch, list, and delete users.",
    "ExerciseDifficulty": "2",
    "DockerImage": "ahmedyh1/grcp_server",
    "port": "5015",
    "DisplayFields": [
      "Name",
      "State.Status",
      "Config.Hostname",
      "NetworkSettings.Networks.bridge.NetworkID"
    ],
    "ClientSide": false,
    "Variables": {
      "host": "",
      "exposedPort": ""
    }
}

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Contributing Guidelines

1. Fork the repository
2. Create a feature branch:

   git checkout -b feature/your-feature

3. Follow existing code style
4. Submit a PR with detailed description

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Visual Enhancements

Client-Side Exercise Example

Portal Interface

Homepage showing available exercises with difficulty levels and descriptions:

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1. Exercise Overview
Students select client-side exercises from the portal. The system provides server container details (IP/port) for connection.

2. Container Details
Real-time container networking information including IP address (10.1.0.2), exposed port (5015), and status:

3. Code Implementation
Students write client code to interact with the server container, with immediate feedback shown:

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Server-Side Exercise Example

1. Exercise Setup
Students launch server-side exercises and receive endpoint details (10.1.0.3:8080) to implement server logic:

2. Container Monitoring
Live view of client containers sending test requests to student servers:

3. Server Implementation
Students write server code and see validation results from test containers:

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Additional Resources

This section contains links to supporting documentation and repositories that complement the Educational Programming Platform.

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📄 Documentation

1. Admin Setup:
   • Admin: How to Deploy the Server
   • Admin: How to Create an Exercise
2. Student Workflow:
   • Student: How to Solve an Exercise

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🛠️ Supporting Repositories

1. Gateway VM Scripts:

   • Repository: gateway-vm-scripts
   • Contains scripts to initialize NGINX and launch the VM gateway into the VXLAN overlay network.

2. Docker Images for Exercises:

   • Repository: Docker-Images-For-Exercise
   • Includes pre-built Docker images and examples of student solutions for exercises.

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🧩 Example Solutions

• Explore example solutions and Docker configurations in the Overlay-Lab Docs.

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