Docker Support

This is just because the format of data output by "docker save" is different than the format of data made available by the v1 API. When doing a sync, the layers retrieved have already been compressed. For unknown reasons, the output of "docker save" created uncompressed files. I think pulp's behavior is correct, unless you saw something to the contrary?

I saw that you you can end up with a mixture of layer formats. If you sync some content from a registry and upload other content into a repository, Pulp ends up storing some layers in compressed format and others as uncompressed tars.

Can you add some info on the consequences of this? Does docker complain or break in some way when it tries to access such a repo?

I don't think it breaks anything. Uncompressed layers just take more space.