4 ms·

I didn’t fully grok how this works - what is the base image for the generated image? Also wouldn’t the image size be large if the glibc is copied over again

• aidenn0 3y ago
  > what is the base image for the generated image? Default is none (i.e. like "FROM scratch" in a Dockerfile); you can specify a baseImage if needed, but I haven't had to yet. It works by copying parts of the nix store into the image as needed, but see also below. > wouldn’t the image size be large if the glibc is copied over again The original Nix docker-tools buildImage did suffer from poor reuse of common dependencies. Docker already has a way to reuse parts of images (e.g. if you build 7 images where the first N lines of a Dockerfile are the same, the 7 images will use a shared store for the results of running the first N lines). There are several backends for Docker storage that accomplish this in various ways (e.g. FS overlays, tricks with ZFS/btrfs snapshots). Nix docker-tools now has a "buildLayeredImage" that uses this ability of Docker to share much of the storage for the dependencies, so if you build several images that all rely on glibc, you only pay the cost of storing glibc in docker once.
  • febed 3y ago
    Thanks, that made the article clearer for me