Packer currently doesn't snapshot the build at each step, so you don't get a history that you can checkout or push from. It's a feature that's on the way, but i

Packer currently doesn't snapshot the build at each step, so you don't get a history that you can checkout or push from. It's a feature that's on the way, but it's a pretty big one that some teams need. We use packer for a lot of other things though and it's great.