Nixos-unstable’s iso_minimal.x86_64-linux is 100% reproducible!

We’ve been hovering close to 100% for a while now but, with the staging-next merge a few days ago, it’s finally happened: (

If I’ve done everything correctly, the 21.05 ISO also passes the check on my machine, hoorray!

Feel free to verify everything yourself; getting @grahamc’s r13y script running is trivial (I’d recommend running it inside a Docker container, though remember to enable sandboxing!)

Next goal: 100% reproducible GNOME ISO :wink:


Here is some general information what this is about and why it matters:

Here are comments to this announcement: Nixos-unstable’s ISO_minimal.x86_64-Linux is 100% reproducible | Hacker News


Incredible work from the community, especially @raboof who consistently kept pushing for the finishing line.


@tomberek shared their result of the GNOME ISO in the r13y matrix channel: Is NixOS Reproducible?


For a while now the ISO is no longer 100% reproducible, anyone have a clue what happened?

1434 out of 1501 (95.54%) paths in the minimal installation image are reproducible!

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The paths are “unchecked”, not “unreproducible” - which means they might in fact be reproducible, but was unable to verify this. This could have any number of reasons, including things like timeouts or exhausted memory or disk space.

For example, manually checking nix-build /nix/store/310735bj7rnfhy1vyrddalz2cfa9f4kl-gzip-1.10.tar.xz.drv --check suggests that derivation is actually fine AFAICS.

To dig deeper perhaps you could have a look at Builds ·