Container Classroom

A collection of scripts to provide on-demand container sandboxes for classes and workshops.

What exactly does it do?

Container Classroom provides scripts that orchestrate lxc, ttyd, and a couple other programs in order to provide a seamless "type in link, get single- use container" workflow. This is in service of the original purpose for which Container Classroom was written, to get workshop goers set up with all the software they need without installing it locally. This allows a workshop holder to hit the ground running without having to deal with poor hackathon network conditions, differences in student workstation configuration, or other tricky issues.

How do I run it?

Given that Container Classroom started as a purpose-built kludge meant solely for my own use, running Container Classroom on your own infrastructure will be rather technical and rather involved. However, I hope to streamline the process, so that it is more accessible. That said, the approximate steps are as follows:

Step 0. Clone this repo

How else are you going to run these scripts?

Step 1. Acquire dependencies

Container Classroom currently requires the following software on the host:

• LXD (For creating and orchestrating containers with commands like lxc launch and lxc stop)
• ttyd (For making TTYs for the containers available via a web browser)
  • You will want to install ttyd to the cloned repo directory, that is where the scripts will look for it.
• figlet and lolcat (For making the cool banners to say "Welcome", these packages aren't essential beyond that)
• The Zsh shell (Since I made the interesting choice to write these as zsh)

Step 2a. Configure LXD network interface

I forget exactly how I did this, but LXD needs to be configured to properly attach containers to a network interface. Optionally, if you want to have internet access inside the containers, you will also have to configure iptables to allow that.

This is probably the most difficult part and as a result the part that I do not have the best documentation about. This section will hopefully be improved.

Step 2b. (Optional) Set up a base container image

The Container Classroom scripts will work with base images like ubuntu;22.04 and friends, but if you want to pre-distribute files for your workshop and/or lesson, you will want to make a container with all the files and users you want and then lxc publish <container> --alias <image> it.

Step 3. Configure the session script

You will want to edit new_ephemeral_container.zsh to include your image name, desired user, and other settings.

Step 4. Run it!

Executing start_service.zsh should launch a tmux session with a log, htop, and a terminal. This can be safely detached, if you don't need it. To kill the Container Classroom system, just run stop_service.zsh.

Things I want to add

• Easier way to get dependencies
• Better documentation around LXD
• Move away from using Zsh
• A web-based control panel

License Notice

Container Classroom is licensed under the Apache License 2.0 license, by Ian Morrill.