Eelco Dolstra, Merijn de Jonge, Eelco Visser. Nix: A Safe and Policy-Free System for Software Deployment. In Proceedings of the 18th Conference on Systems Administration (LISA 2004), Atlanta, USA, November 14-19, 2004. pages 79-92, USENIX, 2004.
Existing systems for software deployment are neither safe nor sufficiently flexible. Primary safety issues are the inability to enforce reliable specification of component dependencies, and the lack of support for multiple versions or variants of a component. This renders deployment operations such as upgrading or deleting components dangerous and unpredictable. A deployment system must also be flexible (i.e., policy-free) enough to support both centralised and local package management, and to allow a variety of mechanisms for transferring components. In this paper we present Nix, a deployment system that addresses these issues through a simple technique of using cryptographic hashes to compute unique paths for component instances.