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Creating static deltas

OSTree downloads updates from a remote OSTree repository. OSTree repositories contain all the files that compose some version of an image. When you create and manage images with OSTree, you can also create static deltas. Static deltas are a collection of updates generated between two OSTree commits. Static deltas optimize updates by fetching only objects from the new commit that do not already exist in the image. If a static delta is available for a specific transaction, OSTree will automatically use it.

Prerequisites

Procedure

  1. Run ostree log to get the commit IDs of the available versions:

    $ ostree log --repo=ostree-repo <ostree-repo-name> <distro>/<architecture>/<target>-<manifest-name>

    For example:

    $ ostree log --repo=my-repo autosd9-sig/x86_64/qemu-ostree_upgrade
commit 5c94cb5ee2409b0219e8d3cf3bda1b56dafb9dcbc0846da97309491524e4fcee
Parent:  8be6158fa1862950d8751663728bdb82d1c7d537770b1f0fc9b8eba4939480ae
ContentChecksum:  8c82a9801802d726e546bf9475f719c3760e660f8165bd034876e04aa84092d1
Date:  2025-05-06 18:28:23 +0000
Version: 1.1
(no subject)

commit 8be6158fa1862950d8751663728bdb82d1c7d537770b1f0fc9b8eba4939480ae
ContentChecksum:  422d0de2ea20a009a754b699d3ca65ea7db1881bfa7c6c254258b84fa3c9ce9b
Date:  2025-05-06 18:11:26 +0000
Version: 1.0

    There are two commits. Version 1.1, the most recent commit, has the ID 5c94cb5ee2. Its parent commit, 8be6158fa1, matches the commit ID for Version 1.0.

  2. Generate a static delta using the following syntax:

    $ sudo ostree static-delta generate --repo=<ostree-repo-name> --from=REV --to=REV

    The REV values are the commit IDs of the versions between which you want to create a static delta. The example, which uses partial commit IDs, creates a static delta from Version 1.0 to Version 1.1:

    $ sudo ostree static-delta generate --repo=my-repo --from=8be6158fa1 --to=5c94cb5ee2

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