nixos-generators
A collection of image builders for NixOS, now upstreamed into nixpkgs and replaced by nixos-rebuild build-image.
What is nixos-generators?
nixos-generators was a collection of image builders for NixOS that allowed users to generate system images for various platforms and formats from a single NixOS configuration. It solved the problem of manually creating deployment artifacts for different environments by providing a unified tool. The project has been deprecated as its functionality is now integrated into nixpkgs via the `nixos-rebuild build-image` command.
NixOS users and system administrators who need to deploy NixOS across multiple platforms like cloud providers, virtual machines, or physical hardware.
It offered a consistent, declarative way to build images for diverse targets from one configuration, reducing complexity and ensuring reproducibility. Developers chose it for its extensive format support and integration with the Nix ecosystem.
Overview
Collection of image builders [maintainer=@Lassulus]
Use Cases
Best For
- Building NixOS images for cloud platforms like AWS, Azure, or GCP
- Creating installation ISOs or SD card images for physical hardware
- Generating virtual machine images for VirtualBox, VMware, or Hyper-V
- Deploying NixOS in containerized environments like Docker or LXC
- Producing images for specialized systems like Proxmox or KubeVirt
- Migrating from nixos-generators to the upstream nixpkgs image builders
Not Ideal For
- New projects starting with NixOS that should use the standard, upstream nixpkgs tooling from the beginning
- Production environments requiring guaranteed long-term support, security updates, and active maintenance
- Users who need specific legacy output formats or commands from nixos-generators without flexibility to adapt to new methods
- Teams unwilling to invest time in migrating configurations to the new `nixos-rebuild build-image` workflow
Pros & Cons
Pros
Supported over 20 image formats including cloud providers (AWS, Azure), virtual machines (VMware, VirtualBox), and containers (Docker, LXC), as detailed in the comprehensive format table.
Enabled building images for diverse platforms from a single NixOS configuration, reducing manual setup and ensuring consistency across deployments.
Used for 8 years and built countless images, demonstrating reliability and widespread adoption before its functionality was upstreamed into nixpkgs.
Provides clear documentation and a format compatibility table to help users transition to the new `nixos-rebuild build-image` command.
Cons
Officially deprecated as of NixOS 25.05, meaning no new features, bug fixes, or security updates, forcing users to migrate for future compatibility.
Switching to upstream requires learning new commands and may involve configuration changes, with some formats like Docker having limitations (e.g., 'probably only works in podman') or requiring customization.
The new `nixos-rebuild build-image` command might not perfectly replicate all behaviors or outputs of nixos-generators, leading to adjustment periods and troubleshooting.
Frequently Asked Questions
Related Projects
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