Built on top of the OSTree versioning filesystem core is a layer that knows how to deploy, parallel install, and manage Unix-like operating systems (accessible via ostree admin). The core content of these operating systems are treated as read-only, but they transparently share storage.

A deployment is physically located at a path of the form /ostree/deploy/osname/deploy/checksum. OSTree is designed to boot directly into exactly one deployment at a time; each deployment is intended to be a target for chroot() or equivalent.