TL;DR;
- More secure foundation for referencing images and layers
- New distribution manifest and pull features
- Upgrading old images will include a migration step
- A migration tool exists in order to minimize migration time
This post describes the upcoming changes to the way Docker Engine stores images and filesystem data in containers. These changes are coming to users starting from version v1.10. (FIXME: link to download rc1)
Starting from v1.10 we completely change the way we address the image data on disk. Previously, every image and layer used a randomly assigned UUID, now we have opted for a content addressable method and use an ID that is based on as secure hash of the image and layer data.