Efficient and Cost-Effective HPC on the Cloud

HPC applications are increasingly utilizing cloud resources due to their cost-effectiveness. Among these resources, spot compute instances present an opportunity to run applications at deep discounts compared to on-demand instances. However, they present unique challenges for tightly-coupled HPC applications due to potential interruptions. Traditional parallel programming models like MPI are not inherently fault-tolerant, and existing methods to handle these interruptions are inefficient and require significant programmer effort. In this paper, we present Charm++ as an alternative solution that natively supports fault tolerance, dynamic load balancing, and resource rescaling. We present a tool to run Charm++ applications with a mix of on-demand and spot instances which can detect and efficiently handle spot interruptions without a shared filesystem. We show that using spot instances can result in up to 60% cost savings for our benchmark application.