Snap seeding a classic image - latest process

Hi,

Having tested seeding a classic image previously. I recently looked at the process again and found that it seems to have changed a bit. But, I can’t find any good docs about it.

Firstly, I understand that ubuntu-image now seems to fully support creating a classic image and seeing it in a single process. But, without going into too much detail on that here, I found that to be not super well documented and even a little problematic for my use case, so initially I’m not pursuing that.

Instead, I’m trying to generate the snap seed info separately, and add it to a pre-existing image, such as an ubuntu cloud image. This used to be a documented approach [ shared with us when we initially received our Brand Store ].

I’m using a command of the form snap prepare-image --classic model.assert seed/

This used to generate a seed directory, containing files in this kind of structue:

seed/
seed/snaps/*.snap
seed/assertions/*.assert
seed/seed.yaml

Then, you would simple add that info to /var/lib/snapd/seed and force snapd re-install.

Now, when I generate the seed info using snap prepare-image --classic It generates a structure like:

seed/system-seed
seed/system-seed/snaps
seed/system-seed/systems/{date}
seed/system-seed/systems/{date}/assertions/snaps
seed/system-seed/systems/{date}/assertions/model-etc
seed/system-seed/systems/{date}/snaps/aux-info.json

What is the process to add that seed structure to a pre-existing image ?

Is the current process documented anywhere ?

Thanks!

Cheers, Just