Have you tried dockerTools.buildLayeredImage (https://nixos.org/manual/nixpkgs/stable/#ssec-pkgs-dockerTools-buildLayeredImage https://nixos.org/manual/nixpkgs/

Have you tried dockerTools.buildLayeredImage (https://nixos.org/manual/nixpkgs/stable/#ssec-pkgs-dockerTools-buildLayeredImage https://nixos.org/manual/nixpkgs/stable/#ssec-pkgs-dockerToo...)? It applies some smart heuristics (https://grahamc.com/blog/nix-and-layered-docker-images https://grahamc.com/blog/nix-and-layered-docker-images) to create images made of pretty reusable layers. This is subject to some false cache misses due to some laziness in the docker's cache implementation (https://github.com/moby/moby/issues/38446 https://github.com/moby/moby/issues/38446), but that is Docker's fault not nix's and it affects dockerfile builds too.