Fedora CoreOS is an automatically updating, minimal, monolithic, container-focused operating system, designed for clusters but also operable standalone, optimized for Kubernetes but also great without it. Its goal is to provide the best container host to run containerized workloads securely and at scale.

Fedora CoreOS is an open source project associated with the Fedora Project.

Ignition is a utility created to manipulate disks during the initramfs. This includes partitioning disks, formatting partitions, writing files (regular files, systemd units, etc.), and configuring users. On first boot, Ignition reads its configuration from a source of truth (remote URL, network metadata service, hypervisor bridge, etc.) and applies the configuration.

• Butane

FreeCAD, a Free and Open-Source (FOSS) 3D CAD modeling platform, offers BIM tools since many years with the Arch workbench. Starting from version 1.0, released in November 2024, the Arch tools have been extended and renamed to become the BIM workbench, and extended with a new native IFC system. This tutorial will walk you through the different concepts used in native IFC, and how to apply them working on an example model.

Butane (formerly the Fedora CoreOS Config Transpiler, FCCT) translates human readable Butane Configs into machine readable Ignition Configs. See the getting started guide for how to use Butane and the configuration specifications for everything Butane configs support.

• Ignition

This project is now known as “libostree”, though it is still appropriate to use the previous name: “OSTree” (or “ostree”). The focus is on projects which use libostree’s shared library, rather than users directly invoking the command line tools (except for build systems). However, in most of the rest of the documentation, we will use the term “OSTree”, since it’s slightly shorter, and changing all documentation at once is impractical. We expect to transition to the new name over time.

As implied above, libostree is both a shared library and suite of command line tools that combines a “git-like” model for committing and downloading bootable filesystem trees, along with a layer for deploying them and managing the bootloader configuration.

The core OSTree model is like git in that it checksums individual files and has a content-addressed-object store. It’s unlike git in that it “checks out” the files via hardlinks, and they thus need to be immutable to prevent corruption. Therefore, another way to think of OSTree is that it’s just a more polished version of Linux VServer hardlinks.

Features:

• Transactional upgrades and rollback for the system
• Replicating content incrementally over HTTP via GPG signatures and “pinned TLS” support
• Support for parallel installing more than just 2 bootable roots
• Binary history on the server side (and client)
• Introspectable shared library API for build and deployment systems
• Flexible support for multiple branches and repositories, supporting projects like Flatpak which use libostree for applications, rather than hosts.