Vsys: A Programmable sudo

Abstract

We present Vsys, a mechanism for restricting access to privileged operations, much like the popular sudo tool on UNIX. Unlike sudo, Vsys allows privileges to be constrained using general-purpose programming lan- guages and facilitates composing multiple system ser- vices into powerful abstractions for isolation. In use for over three years on PlanetLab, Vsys has enabled over 100 researchers to create private overlay networks, user- level file systems, virtual switches, and TCP-variants that function safely and without interference. Vsys has also been used by applications such as whole-system monitoring in a VM. We describe the design of Vsys and discuss our experiences and lessons learned.