The actual content layers (i.e. those containing Nix store paths) are going to be the same, but metadata layers (those containing the image name and the references to all layers) are currently going to be cache-busted.
I'll look into getting that fixed - as long as Docker doesn't mind seeing a different image name than it requested in the manifest it shouldn't be an issue to return the metadata in a stable order.
The actual content layers (i.e. those containing Nix store paths) are going to be the same, but metadata layers (those containing the image name and the references to all layers) are currently going to be cache-busted.
I'll look into getting that fixed - as long as Docker doesn't mind seeing a different image name than it requested in the manifest it shouldn't be an issue to return the metadata in a stable order.