For most students, lessons in the computer lab are a welcome change from the traditional classroom setting. However, especially for younger elementary students, learning on a computer can also be a distraction, making it hard for teachers to keep a student's attention on the current lesson.

Digital classroom management software can help solve this issue by letting the teacher control the students' computers to ensure that the screen content does not constantly distract students. Linux offers several open source management solutions for school computer labs, including the well-known Veyon [1].

In this article, I explore another option, Epoptes (Greek for overseer) [2]. Epoptes offers an equally sophisticated client-server solution for managing and monitoring Linux-based computer labs, with the added advantage of being easy to set up and maintain.

Functions

Epoptes maintains separate packages for the server (the teacher's computer) and the clients (the students' computers), with precompiled binaries available in the respective repositories for Debian, Ubuntu, Fedora, and openSUSE. Epoptes can also be integrated into derivative distributions, such as Linux Mint. For Arch Linux, the software can be found in the Arch User Repository (AUR).

The Epoptes server is used to control heterogenous client environments; the students' computers do not have to run on the same distribution, but they must be Linux environments (it does not support other operating systems such as Windows or macOS). Epoptes opens a connection between the server and the clients via encrypted reverse VNC channels, with certificates serving as the authentication mechanism.

Epoptes combines classic control tools, allowing the client systems to be turned on and off, as well as locked individually. Epoptes supports monitoring and controlling each student computer, as well as broadcasting the teacher's screen (the server) to the client displays. In addition, the server can also remotely execute commands on the students' systems and send messages to them.

Installation

Epoptes is a 64-bit application that requires corresponding versions of the supported Linux distributions. It can be conveniently set up from the respective repositories using the distribution's own graphical front ends. You install the server package (epoptes) on the teacher's computer and then the client package (epoptes-client) on each student's computer.

To run the server, you still need to create an epoptes group on the teacher's computer. Using the commands from Listing 1, you then join the group and log in. The next step is to start the Epoptes server with the desktop menu; this takes you to a clear-cut administration window (Figure 1).

$ sudo usermod aG epoptes $USER
$ newgrp -- epoptes

Figure 1: The administration window on the teacher's computer is self-explanatory.

For the clients and the server to connect, you next need to tell the clients the location of the server system using the /etc/default/epoptes-client file. Open this file in any editor and specify the DNS name of the server machine in the SERVER= line. Alternatively, if you run the server machine with a static IP, you can also enter the server's address and hostname in the /etc/hosts file on the students' machines.

To ensure secure communication between the clients and the server, load the server's certificate onto the client computers in a final configuration step. To do this, call

sudo epoptes-client -c

on each client and then reboot.

Getting Started

Upon start-up on the teacher's computer, Epoptes automatically connects to the switched-on student computers. After a moment, a thumbnail preview of each student desktop appears in the right pane of the program window (Figure 2). Following the client hostnames, Epoptes displays the name of the respective logged-in user.

Figure 2: The Epoptes server automatically finds active clients on the intranet.

To control a student computer remotely, simply double-click on the corresponding thumbnail. TigerVNC [3], which is implemented in Epoptes, opens a large window with the selected computer desktop. From the teacher's computer, you can now control the selected client's computer using keyboard and mouse input.