The Open Source Virtual Lab: a Case Study Authors: E. Damiani, F. Frati, D. Rebeccani, M. Anisetti, V. Bellandi and U. Raimondi University of Milan Department of Information Technology

Introduction Thanks to Internet technologies, it is now possible to offer courses (and laboratories) on the web that satisfy all functionalities of conventional courses. Providing hands-on experience by using computer and making exercises on network configurations and security-related issues are essential for Information Technologies education.

The Goal Fully Open Source Virtual Laboratory Remote Access Integration with “CdL online” platform of University of Milan

System Description The system is composed by: e-Learning platform, that allows the access to courses contents, to the Virtual Lab and the interactions with tutors and teachers; Virtual Laboratory, that implements an informatics laboratory which provides students with a real working environment; it consists of a VMs pool, a virtualization server and a firewall; student web browser, that allows to connect and interact with the platform and runs an applet to connect to the assigned VM.

Virtual Lab Framework The system framework of Virtual Lab can be examined focusing on three aspects:  Hardware  Virtualization software  Virtual Machines

Hardware Two different real machines: 1. Virtual Lab Server with Spacious storage Big RAM memory 2. Firewall Preserve virtual server performance Increment system security Isolate virtual machines from external environment

The Virtualization Software: Xen Created by University of Cambridge Its paravirtualized virtual machine monitor ( hypervisor ) permits to achieve performance close to native hardware.

Virtual Machines Virtual Machine is an isolated duplicate of a real machine VM works in a sealed environment VMs are based on Gentoo Linux distribution

Network Configuration Students of the same academic year share the same subnet Static IP ( x) is assigned to each VM VMs share a common gateway

Firewall Configuration Protect the server from external attacks Isolate VMs from the external net  A VM can communicate with any VM on any port  Only ssh connections with the external net are permitted Connections from student computer are forwarded to the relative VM  Each student is associated to a specific server port

System Architecture

Platform connection (1) VMs on demand  VM activation: based on student ID Open a ssh session  Start a ssh client applet (MindTerm) Stop VMs when students close ssh session

Platform connection (2)

Future Works Enhancement in VMs management  Nightly back-up of students home directory  Scripts for software updates and new packages installation New and more complex network topologies  Each student will own a private subnet (e.g. three VMs that act as client computer, web server, and firewall)

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