ThanOS

A lightweight OS used for boot-to-browser thin clients

Architecture

The ThanOS project aims to provide a lightweight, portable OS than can be used for a wide variety of applications, through the use of containers. The key aims of this new project:

• Immutable output
• Ease of build
• Lean / simple design
• Clean base to build upon

The ThanOS project predominantly uses linuxkit as the toolkit that will produce repeatable and straightforward build of the entire in-memory operating system. The linuxkit project combines a Linux kernel with a number of additional container images to produce a Linux Operating System with just the right amount of functionality (no less / no more). We have built upon the minimal set of components:

• containerd (the engine to start/stop all other components in a LinuxKit OS)
• dhcp (for network access)
• ntp (network time)
• rngd (random number gen for entropy)
• sshd (for ssh access)

To this minimal build, we've added our own service that will provide the functionality needed for applications that generate visual and audio outputs to run successfully:

Corvus

The corvus service builds upon the upstream dind (docker-in-docker) container and adds the additional packages required to initialize and run an X11 and ALSA server.

The start.sh, once run, executes a number of steps:

1. Install, configure and start the X11 server
2. Unmute the master output in ALSA
3. Read the X and Y resolution from the config file located at /var/lib/docker/config
4. Set the screen resolution to the values read in from the config file
5. Launch a new private Firefox session, and navigate to the url also read in from the config file

NOTE: ThanOS is designed to be installed through the Tinkerbell provisioning engine. As such, if installed without Tinkerbell, you will not have the config file and will most likely have the screen resolution set to the X server default 800x600.

Pixel Streaming

One of the use cases ThanOS is primarily designed for, is to be a thin client that runs a web browser with the intention of receiving a pixel streaming output.
We've included the necessary drivers to have audio and video output, as well as keyboard and mouse input.

For users wanting to use ThanOS in a pixel streaming deployment, point the url field in the writefile action of your Tinkerbell template to the address of your pixel streaming application.

eg http://mypixelstreamingurl

Building ThanOS

Working on an Ubuntu 20.04 host

# Clone this repo
git clone https://github.com/belchy06/ThanOS

# Generate ssh keys
ssh-keygen -t rsa -b 4096 -C "your_email@domain.com"

# build it - this produces a virtual box VHD file
make

Building other output formats

The LinuxKit project can generate a wide variety of output formats. See linuxkit build -help for the complete list of output formats available. Once you have identified your target format, you can specify it with:

make FORMAT=your-format

Troubleshooting

You can ssh into your machine once it is running on port 1234. NOTE: You may need -o StrictHostKeyChecking=no in your connection command. eg

ssh -o StrictHostKeyChecking=no x.x.x.x -p 1234 -l root