libOSTree

New! See the docs online at Read The Docs (OSTree)


This project is now known as "libOSTree", renamed from "OSTree"; the focus is on the shared library. 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.

libOSTree is a 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 should thus be immutable. Therefore, another way to think of OSTree is that it's just a more polished version of Linux VServer hardlinks.

Features:

  • Atomic 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

This last point is important - you should think of the OSTree command line as effectively a "demo" for the shared library. The intent is that package managers, system upgrade tools, container build tools and the like use OSTree as a "deduplicating hardlink store".

Projects using OSTree

meta-updater is a layer available for OpenEmbedded systems.

QtOTA is Qt's over-the-air update framework which uses libostree.

rpm-ostree is a next-generation hybrid package/image system for Fedora and CentOS, used by the Atomic Host project. By default it uses libostree to atomically replicate a base OS (all dependency resolution is done on the server), but it supports "package layering", where additional RPMs can be layered on top of the base. This brings a "best of both worlds"" model for image and package systems.

flatpak uses libostree for desktop application containers. Unlike most of the other systems here, flatpak does not use the "libostree host system" aspects (e.g. bootloader management), just the "git-like hardlink dedup". For example, flatpak supports a per-user OSTree repository.

Endless OS uses libostree for their host system as well as flatpak. See their eos-updater and deb-ostree-builder projects.

GNOME Continuous is where OSTree was born - as a high performance continuous delivery/testing system for GNOME.

Building

Releases are available as GPG signed git tags, and most recent versions support extended validation using git-evtag.

However, in order to build from a git clone, you must update the submodules. If you're packaging OSTree and want a tarball, I recommend using a "recursive git archive" script. There are several available online; this code in OSTree is an example.

Once you have a git clone or recursive archive, building is the same as almost every autotools project:

env NOCONFIGURE=1 ./autogen.sh
./configure --prefix=...
make
make install DESTDIR=/path/to/dest

More documentation

New! See the docs online at Read The Docs (OSTree)

Contributing

See Contributing.