High-performance computing clusters (commodity hardware with low-latency, high-bandwidth interconnects) based on Linux, are rapidly becoming the dominant computing platform for a wide range of scientific disciplines.Yet, straightforward software installation, maintenance, and health monitoring for large-scale clusters has been a consistent and nagging problem for non-cluster experts.The NPACI Rocks toolkit takes a fresh perspective on management and installation of clusters to dramatically simplify software version tracking, and cluster integration.The toolkit incorporates the latest Red Hat distribution (including security patches) with additional cluster-specific software.Using the identical software tools used to create the base distribution, users can customize and localize Rocks for their site.Strong adherence to widely-used (\emph{de facto}) tools allows Rocks to move with the rapid pace of Linux development.Version 2.1 of the toolkit is available for download and installation.To date, 10 clusters spread among 5 institutions have been built using this toolkit.