Quattor is a generic open-source tool-kit used to install, configure, and manage computers. Quattor was originally developed in the framework of European Data Grid project (2001-2004). Since its first release in 2003, Quattor has been maintained and extended by a volunteer community of users and developers, primarily from the community of grid system administrators. The Quattor tool-kit, like other configuration management systems, reduces the staff required to maintain a cluster and facilitates reliable change management. However, three unique features make it particularly attractive for managing grid resources: Federated Management: The open, modular nature of the tool-kit permits system administrators at different institutes to share the management of their distributed resources. Shared Configuration and Management Efficiency: Quattor encourages the re-use of configuration information in such a way that it can be distributed and used with little or no modification at different sites, facilitating the distribution of best practices without the need for each site to implement configuration changes. Coherent Site Model: Quattor allows an administrator to develop a site model that, once constructed, can be used to manage a range of different resources, such as real machines, virtual machines and cloud resources. These features are also attractive beyond the grid context. This has been confirmed by the growing adoption of Quattor, by both large commercial organisations and academic institutions, most of them using the tool-kit to manage consistently their grid and non-grid systems. Principles The challenge of structuring and sharing components in a collaborative system is not new; over the years programming language designers have attacked this problem from many angles. While trends change, the basic principles are well understood. Features such as encapsulation, abstraction, modularity, and typing produce clear benefits. We believe that similar principles apply when sharing configuration information across administrative domains. The Quattor configuration tool-kit derives its architecture from LCFG, improving it in several aspects. At the core of Quattor is Pan, a high-level, typed language with flexible include mechanisms, a range of data structures, and validation features familiar to modern programmers. Pan allows collaborative administrators to build up a complex set of configuration templates describing service types, hardware components, configuration parameters, users etc. The use of a high-level language facilitates code reuse in a way that goes beyond cut-and-paste of configuration snippets. The principles embodied in Quattor are in line with those established within the system administration community. In particular, all managed nodes retrieve their configurations from