ostreebacked

Ostree-backed refers to systems whose operating system core is versioned and delivered using OSTree. OSTree is a tool and content-addressed filesystem that stores the root filesystem as commits, enabling atomic upgrades, rollbacks, and multiple deployments.

How it works: The OS maintains a set of deployments in a dedicated tree, with each deployment corresponding to a commit. The bootloader selects the active deployment at boot time. Updates create a new deployment commit, and rebooting switches to that commit. In many setups, a separate mechanism such as rpm-ostree can layer RPM packages on top of the base ostree tree, allowing user-visible applications to be installed while preserving the ability to revert the entire system to a previous state.

Usage and landscape: Ostree-backed deployments are common in immutable or release-centric Linux environments. Notable examples include Fedora Silverblue, which uses ostree as the base with rpm-ostree for package layering, and Fedora CoreOS, which employs similar concepts for automatic, reliable updates. The approach emphasizes stability, reproducibility, and predictable upgrades rather than continuous, piecemeal changes.

Advantages: Atomic upgrades and rollbacks reduce the risk of partial or failed updates. The system state is highly reproducible, enabling easy debugging and recovery. Multiple independent deployments can coexist, facilitating testing or different configurations without affecting the running system.

Limitations: Ostree-backed systems typically rely on a separate packaging workflow, and are not built around a traditional package manager for the base OS. Some workloads or tooling may require additional layering or migration paths. The model can introduce complexity for users accustomed to standard package management and may have a steeper learning curve.

See also: OSTree, rpm-ostree, immutable operating systems, Fedora Silverblue, Fedora CoreOS.