Albius is a Linux installer backend originally designed for Vanilla OS, but capable of handling any Linux distribution that uses either Squashfs or OCI images for distributing the base system. Albius is written entirely in Go and uses a recipe system (see "recipes" subsection) for describing operations, mountpoints and options.
Given the unorthodox filesystem structure present in Vanilla OS, most installers are unable to handle the distribution's installation without also requiring several patches. Furthermore, as we aim to provide a cohesive user experience starting with the installation process, Vanilla OS uses a custom frontend written in Python, further complicating the integration with other backends.
As Albius is written from the ground up to work with recipes, it can be used by any installation frontend or no frontend at all. The goal is to provide a simple CLI tool that reads a configuration file generated by another application or by hand and automates all the installation steps.
Recipes are the primary way of configuring Albius and are simply a JSON file
containing setup steps, mountpoints for the target system,
installation options, and post-installation steps. A sample recipe can
be found in recipe_template.json
The full list of operations supported by the recipe system can be found in RECIPE.md.
The setup section is a list of actions to take before starting the installation process itself, such as formatting the disk or creating partitions. Each step contains a target disk, an operation name, and a list of parameters, like in the example below:
"setup": [
{
"disk": "/dev/sda",
"operation": "mkpart",
"params": [
"mypart",
"btrfs",
1,
-1
]
}
]Creates a BTRFS partition in /dev/sda called "mypart" using the entire disk.
This section of the recipe describes where each partition will be mounted to on
the installed system. Just like in the previous section, mountpoints expects a
list containing a partition path (/dev/sdx1, for example) and its corresponding
mountpoint.
"mountpoints": [
{
"partition": "/dev/sda1",
"target": "/"
},
{
"partition": "/dev/sda2",
"target": "/home"
}
]Sets /dev/sda1 as the root partition and /dev/sda2 as the home partition.
The installation section holds options specific to the installation process, such as the installation method and filesystem source. This section contains two installation-related options: "method", which can be either "unsquashfs" or "oci", and "source", which describes a path for the Squashfs filesystem or OCI image repository, depending on the selected method. The other two parameters are related to the initramfs generation, which happens at the end of the installation process. The user can specify optional commands to execute before and after this step, such as unlocking certain binaries or preparing the file scructure.
"installation": {
"method": "unsquashfs",
"source": "/cdrom/casper/filesystem.squashfs"
"initramfsPre": ["my_pre_hook"],
"initramfsPost": ["my_post_hook"]
}Similar to "setup", but this time describing steps for post-installation actions such as user creation, timezone or locale configuration, or distro-specific shell commands. This section expects a list of steps, each containing the following options: whether the operation should run on the installed system (chroot) or on the host, the operation name, and a list of parameters.
"postInstallation": [
{
"chroot": true,
"operation": "adduser",
"params": [
"albius",
"Albius",
[
"sudo",
"lpadmin"
],
"ASuperStrongPassword"
]
}
]Creates the user "albius" with the display name "Albius" that belongs to the "sudo" and "lpadmin" groups and authenticates with "ASuperStrongPassword".
Some system dependencies are required for building Albius:
libbtrfs-devlibdevmapper-devlibgpgme-devlvm2- A C compiler supported by CGo (
gcc, for example)
After the packages listed above have been installed, all that's left to do is run:
$ go buildWriting unit tests for new functionality is encouraged to make sure everything still works. All tests are executed in a loop device created before the tests are started. To execute the test suite, simply run:
$ sudo go test ./... -vSudo is necessary in order to mount the loop device, as well as run some of the
operations. If you're in an immutable base distribution like Vanilla OS and wish
to run the tests in an isolated environment, keep in mind that the tests need
to be executed in a rootful container. You can find a script in utils/create_test_env.sh
that automatically sets up a container for running Albius by using Distrobox.
Albius accepts only one positional argument, which is the path for the recipe it should use to install the system. Remember to always run the binary with elevated privileges like in the example below:
$ sudo albius <path_for_recipe.json>Yes. In fact, Albius was originally tested with Vanilla OS 22.10, which used a
Squashfs installation method with two root partitions. All you have to do is
specify two partitions with "target": "/" inside "mountpoints".
The best way to integrate Albius with a custom installer is by saving all the
user options in a dictionary or hash map with the same structure described in
the sections above, save it to a temporary location (e.g. in /tmp), and then
call Albius by spawning a privileged shell passing the file as a parameter.
According to Wikipedia, Edmond Albius was a horticulturalist credited with inventing a technique for pollinating vanilla orchids that is both quick and efficient, which is still used to this day. Born into slavery in Réunion, Albius discovered the technique at the age of 12, which led the French colony to become the world's largest supplier of vanilla for some time. Although he never received the recognition he deserves and died in poverty at the age of 51, we hope to make more widely known the name of the person responsible for some of our favorite deserts. Furthermore, if an installer can be thought of as the means of reproduction for Linux distributions, then Albius is responsible for spreading Vanilla OS to the world.