Det finns många som den, men den här är min : Personalisering av icke-persistenta utvecklingsmiljöer med Nix

Software development in Highly Regulated Environments (HREs), such as those in defense or healthcare, imposes demands on the development infrastructure. Workstations must be reproducible, mutually consistent across a team, and support traceable modifications. This motivates a strict approach to workstation system management. At the same time, individual developers require the ability to personalize their environment, creating a tension between these regulatory requirements and individual needs. This project explores how non-persistent developer workstations, which reset to a clean state on every boot, can be personalized while retaining properties mandated by regulation. We evaluate the Nix ecosystem as a platform for this purpose, specifically using NixOS and Home Manager, a module for managing the user environment using the Nix package manager and package repository. Two approaches to personalization are compared: applying a Home Manager configuration at NixOS image build time (“pre-boot”) and at runtime after boot (“post-boot”). Both are evaluated based on reproducibility, environment parity with a shared non-personalized baseline, and traceability. We define a base system and a shared personalization configuration, deploy each variant on identical hardware, and analyze the resulting file system states. The results show that both approaches are highly reproducible and offer strong traceability. Pre-boot personalization modifies the baseline more heavily but results in a smaller system state in total (fewer files). In contrast, post-boot personalization leaves the baseline virtually untouched but introduces more artifacts and is a more invasive process. Pre-boot offers stronger guarantees, aligning more closely with regulatory needs, while post-boot is more flexible and offers a simpler build process. After considering the high-level differences between the two approaches, a potential hybrid strategy is discussed, combining their strengths.