Hobbes: A Multi-kernel Infrastructure for Application Composition

This chapter describes the Hobbes OS/R environment, which was designed to support the construction of sophisticated application compositions across multiple system software stacks called enclaves. The core idea of the approach is to enable each application component to execute in the system software environment that best matches its requirements. Hobbes then provides a set of cross-enclave composition mechanisms enabling the individual components to work together as part of a larger application workflow. Unique aspects of Hobbes compared to other multi-kernels include its emphasis on supporting application composition, its focus on providing cross-enclave performance isolation, and its use of hardware virtualization to enable the use of arbitrary OS/Rs. In particular, Hobbes leverages distributed, user-level resource management and hardware virtualization to allow underlying OS kernels to be largely agnostic of the multi-kernel environment, making it straightforward to add support for new OS kernels to Hobbes. We demonstrate Hobbes using a modern Cray XC30m machine, showing the generality of OS/R configurations it supports, as well as its ability to leverage existing unmodified HPC system management tools.