bootc

Transactional, in-place operating system updates that ship the whole host as an OCI (Open Container Initiative) image.

• Category: Runtime
• CNCF maturity: Sandbox
• Language: Rust
• License: MIT OR Apache-2.0 (dual)
• Repository: bootc-dev/bootc
• Documented at commit: a7f95e7 (near tag v1.16.2)

What it is

bootc boots and upgrades a Linux host from a container image. You build a bootable operating system the same way you build an application container: a Containerfile, podman build, and a registry. bootc then installs that image to a disk and applies later versions of the same image tag in place. The repository README states the goal plainly: apply the Docker layer model to bootable host systems, using standard OCI/Docker containers as the transport and delivery format for base operating system updates (README.md:8-12).

A bootc system is not a container at runtime. The container image carries a Linux kernel under /usr/lib/modules, and that kernel is what boots. Once booted, the base userspace is not running inside a container: systemd runs as pid1 as usual, with no outer process (README.md:14-17). The container is purely the packaging and delivery format.

bootc is the successor interface to ostree and rpm-ostree, two projects with the same lineage from Red Hat. It models host state as a Kubernetes-style declarative object and applies updates in an A/B style so a bad update can be rolled back.

When to use it

• You want fleet hosts defined as an immutable image and updated by changing a registry tag, the way you already ship application containers.
• You need atomic, in-place OS updates with a guaranteed rollback slot rather than per-package upgrades through apt or dnf.
• You build base images with existing OCI tooling (podman, buildah, Dockerfiles) and want the host OS to use the same pipeline.
• It is a weaker fit when you need to mutate the running root filesystem freely at runtime, since the deployed /usr is read-only by design.
• It is not the tool for managing application workloads on top of an OS; it manages the OS itself.

In this deep-dive

• History: origin, milestones, and why it exists.
• Architecture: components and how an upgrade flows.
• Adoption & Ecosystem: who runs it and what surrounds it.
• Internals: the code paths that matter, read from source.
• Getting Started: install and a first working setup.

Sources

1. bootc-dev/bootc repository
2. bootc source at commit a7f95e7
3. bootc CNCF project page
4. Making containers bootable for fun and profit (LWN)
5. Changes/OstreeNativeContainerStable (Fedora Project Wiki)
6. bootc website and documentation