aptly's goal is to establish repeatability and controlled changes in package environments.
aptly produces a fixed set of packages in the repository, so that package installation and upgrade becomes deterministic. At the same time aptly is able to perform controlled, fine-grained changes to repository content. aptly allows you to transition your package environment to a new version, or rollback to a previous version.
aptly has several core entities:
The schema of aptly’s commands and transitions between entities:
We can start with creating mirrors of remote
repositories. Also we can create local package
repositories and import package files.
Local repos could be modified by copying and
moving packages between local repositories and
importing them from mirrors. Snapshot could be
created from remote repository (official
Debian repositories, backports, 3rd party repos, etc.) or your local
repository (custom built packages, your own software). Snapshots can be
used to produce new snapshots by filtering
other snapshots, pulling
packages with dependencies between snapshots and by
merging snapshots. Any snapshot can be
published to location (distribution name,
prefix) and consumed by
apt tools on your Debian systems. Local
repositories could be published directly
bypassing snapshot step.
Next section, Why aptly? describes why aptly is unique.