Nix2container Alternatives

nix2container reviews and mentions

• A faster path to container images in Bazel
  5 projects | news.ycombinator.com | 24 Dec 2025

  At runtime, it consumes this JSON file to stream layer data and image configuration to a destination. This is implemented by adding a new transport to Skopeo. Thanks to this implementation, nix2container doesn't need to handle all various destrination since this is managed by Skopeo itself.

  Recently, we introduced a mechanism to also produce such kind of JSON file for the base image (see https://github.com/nlewo/nix2container?tab=readme-ov-file#ni...).

  I'm pretty sure the added (not usptreamed yet) transport could be useful in some other close contexts, such as Bazel or Guix.

  I'm the nix2container author and i will be glad to discuss with you if you think this Skopeo transport could be useful for you!

  (btw, your blog post is pretty well written!)

• Why We're Moving on from Nix
  8 projects | news.ycombinator.com | 7 Jun 2025

  > With no way of splitting up the Nix dependencies into separate layers

  nix2container [1] is actually able to do that: you can explicitly build layers containing a subset of the dependencies required by your image. An example is provided in this section: https://github.com/nlewo/nix2container?tab=readme-ov-file#is...

  For instance, if your images use bash, you can explicitly create a layer containing the bash closure. This layer can then be used across all your images and is only rebuild and repushed if this bash closure is modified.

  > > pull in dependencies often results in massive image sizes with a single /nix/store layer

  This is the case for the basic nixpkgs.dockerTools.buildImage function but this is not true with nix2container, nor with nixpkgs.dockerTools.streamLayeredImage. Instead of writing the layers in the Nix store, these tools build a script to actually push the image by using existing store paths (which are Nix runtime dependencies of this script). Regarding the nix2container implementation, it builds a JSON file describing the Nix store paths for all layers and uses Skopeo to push the image (to a Docker deamon, a registry, podman, ...), by consuming this JSON file.

  (disclaimer: i'm the nix2container author)

  [1] https://github.com/nlewo/nix2container

• Dagger Shell: Unix Pipeline Pattern for Typed API Objects
  8 projects | news.ycombinator.com | 27 Mar 2025
• Nix is a better Docker image builder than Docker's image builder
  21 projects | news.ycombinator.com | 15 Mar 2024

  No discussion about Nix-built containers is complete with nix2container:

  https://github.com/nlewo/nix2container

  It is truly magical for handling large, multi-layered containers. Instead of building the container archives themselves and storing them in the nix store, it builds a JSON manifest that is consumed by a lightly patched version of skopeo that streams the layers directly to either your local container engine or the registry.

  This means you never rebuild or reupload a container layer that is unchanged.

• Way to get NVM working in CI/CD systems
  6 projects | news.ycombinator.com | 19 May 2023

  - Container images are built with https://github.com/nlewo/nix2container instead of Nix's built-in docker tools, because nix2container allows configuration of layers and thus makes it easier to share layers between images and improve layer caching.

  As for integrating it into our CI pipeline, this is pretty much CI system agnostic as all you have to do is run `nix build ...` inside the pipeline, generating a `result` directory or file as an artifact that, in the case of nix2container, can be pushed to your container image registry.

• How do I create a docker image for postgres with nix?
  4 projects | /r/NixOS | 10 Mar 2023

  dockerTools is the canonical way, but https://github.com/nlewo/nix2container seems to be gaining support as it's faster and doesn't use so much disk space while building.

• We deploy 5X faster with warm Docker containers
  3 projects | news.ycombinator.com | 7 Mar 2023

  > The key factor behind our decision was the realization that while Docker images are industry standard, moving around 100s of megabytes of images seems unnecessarily heavy-handed when we just need to synchronize a small change.

  I think the culprit is more the GitHub Actions cache than Docker since it seems to be hard to get a clean cache management. I'm not sure about caching Docker image layers, but caching the Nix store with GitHub Actions is pretty complicated (not even sure it's possible): this means we have to download all required Nix store paths on each run, but i consider this is because of a GitHub Action cache limitation.

  So, did you consider using another CI, which offers better caching mechanisms?

  With a CI able to preserve the Nix store (Hydra[1] or Hercules[2] for instance), I think nix2container (author here) could also fit almost all of your requirements ("composability", reproducibility, isolation) and maybe provide better performances because it is able to split your application into several layers [2][3].

  Note i'm pretty sure a lot of Docker CI also allows to efficiently build Docker images.

  [1] https://hercules-ci.com/

  [2] https://grahamc.com/blog/nix-and-layered-docker-images

  [3] https://github.com/nlewo/nix2container/blob/85670cab354f7df6...

• Launch HN: Depot (YC W23) – Fast Docker Images in the Cloud
  6 projects | news.ycombinator.com | 22 Feb 2023

  FYI, the nix2container [1] project (author here) aims to speedup the standard Nix container workflow (dockerTools.buildImage) by basically skipping the tarball step: it directly streams non already pushed layers.

  [1] https://github.com/nlewo/nix2container

• Crafting container images without Dockerfiles
  20 projects | news.ycombinator.com | 6 Feb 2023

  To get Rust incremental builds, did you consider using something such as crane https://github.com/ipetkov/crane ?

  And regarding OCI images, i built nix2container (https://github.com/nlewo/nix2container) to speed up image build and push times.

• Optimising Docker Layers for Better Caching with Nix (2018)
  2 projects | news.ycombinator.com | 11 Sep 2022

  For a more modern iteration of that idea, check out https://github.com/nlewo/nix2container

  It has all the benefits of OP but produces the images much faster, and with less on-disk usage.

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