Simple flake example to build docker images for different platforms

Quick Start (no checkout required)

ARM (aarch64-linux):

$ nix build github:MaxDaten/flake-cross-container-example#hello-aarch64-linux
$ skopeo inspect docker-archive:result | jq -r '.Os, .Architecture'
linux
arm64

x86 (x86_64-linux):

$ nix build github:MaxDaten/flake-cross-container-example#hello-x86_64-linux
$ skopeo inspect docker-archive:result | jq -r '.Os, .Architecture'
linux
amd64

Extended Guide

To build images for different platforms using nix build, follow these steps:

1. Ensure you have Nix installed on your system. If not, you can install it using the following command:

   curl -L https://nixos.org/nix/install | sh

   And make sure flake support is enabled. You can do this by adding the following line to your ~/.config/nix/nix.conf file:

   experimental-features = nix-command flakes
   

2. Run the following command to build the image:

   For example, to build the image for aarch64-linux, you can use the following command:

   $ nix build .#hello-aarch64-linux
   $ skopeo inspect docker-archive:result | jq -r '.Os, .Architecture'
   linux
   arm64

The pattern for the build targets is .<name>-<platform>.

Please note that the available platforms are defined in the allSystems attribute of the flake.nix file. In this case, the available platforms are x86_64-darwin, aarch64-darwin, x86_64-linux, and aarch64-linux.