Download and Run an Emulator

Download and Run an Emulator #

The easiest way to get started with RACCOON OS is to use the emu.py script. Alternatively, you can download and install the OS on a supported machine.

The emu.py script downloads the bootloader and filesystem for the image that you choose, creates a backing virtual disk drive, and runs the emulator. You must have qemu-system-x86_64 and python3 installed on your computer.

Create a directory to follow along, download the emu.py script and make it executable:

$ mkdir -p dev/raccoon_hello_world
$ wget https://raccoon.jdiez.me/emu.py
$ chmod +x emu.py

Feel free to read the emu.py script before executing it. It’s a very simple Python script that doesn’t need elevated privileges. The CI/CD system deploys emu.py directly from the git repository. Let’s run it:

$ ./emu.py -i raccoon-image-dev -p dev-emulator

The following things happened:

  • the dev-emulator folder was created
  • the following files were downloaded: u-boot-qemux86-64.rom and raccoon-image-dev-qemux86-64.rootfs.ota-btrfs
  • an overlay.qcow2 virtual drive was created
  • u-boot loaded the boot configuration and started the kernel
  • the system connected to the virtual network and started a SSH server

The VM’s SSH port 22 is forwarded to port 2221 on the host. So let’s connect to it:

$ ssh -o StrictHostKeyChecking=no root@localhost -p 2221

Why do we need StrictHostKeyChecking=no? This is because when you decide to recreate the VM (for example, to test a new OS build), a new SSH host key will be generated - and your SSH client will show a warning about a potential man-in-the-middle attack.

When we connect, we are greeted by a banner reminiscent of installing Slackware from a CD-ROM in the 2000s:

$ ssh -o StrictHostKeyChecking=no root@localhost -p 2221
Welcome to...
______  ___  _____  _____  _____ _____  _____ _   _   _____ _____ 
| ___ \/ _ \/  __ \/  __ \/  __ \  _  ||  _  | \ | | |  _  /  ___|
| |_/ / /_\ \ /  \/| /  \/| /  \/ | | || | | |  \| | | | | \ `--. 
|    /|  _  | |    | |    | |   | | | || | | | . ` | | | | |`--. \
| |\ \| | | | \__/\| \__/\| \__/\ \_/ /\ \_/ / |\  | \ \_/ /\__/ /
\_| \_\_| |_/\____/ \____/ \____/\___/  \___/\_| \_/  \___/\____/ 
                                                                  
version 0.4 - yocto scarthgap - now with 100% more OTA!

root@qemux86-64:/var/rootdirs/home/root#

Let’s take a look at the filesystem setup we have out of the box:

root@qemux86-64:/var/rootdirs/home/root# df -kh
Filesystem                Size      Used Available Use% Mounted on
/dev/sda                250.3M    130.2M     54.4M  71% /sysroot
/dev/sda                250.3M    130.2M     54.4M  71% /
/dev/sda                250.3M    130.2M     54.4M  71% /boot
/dev/sda                250.3M    130.2M     54.4M  71% /usr
/dev/sda                250.3M    130.2M     54.4M  71% /var
devtmpfs                470.0M         0    470.0M   0% /dev
tmpfs                   478.0M    128.0K    477.9M   0% /run

We can expand it to fill the whole disk:

# btrfs filesystem resize max /
Resize device id 1 (/dev/sda) from 250.25MiB to max
# df -kh
Filesystem                Size      Used Available Use% Mounted on
/dev/sda                 10.0G    130.2M      9.8G   1% /sysroot
/dev/sda                 10.0G    130.2M      9.8G   1% /
[...]

You can also setup data redundancy (also known as RAID1) to make the filesystem robust against single bit flips.

What can we do from here? At the moment, not much. RACCOON OS ships a versioned, immutable-by-default filesystem. This is necessary for low bandwidth Delta Updates. Learn about installing packages in the next tutorial.

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