Exascale Workflow Applications and Middleware: An ExaWorks Retrospective

TL;DR

The paper reviews the ExaWorks project, which develops tools and APIs to facilitate the deployment and interoperability of complex workflows on exascale HPC platforms, enhancing scientific computing capabilities.

Contribution

It introduces the ExaWorks workflow SDK and PSI/J API, providing standardized, portable solutions for managing workflows and jobs across diverse HPC systems.

Findings

Development of a unified workflow SDK for HPC

Introduction of PSI/J API for portable job management

Implementation of workflows on DOE leadership platforms

Abstract

Exascale computers offer transformative capabilities to combine data-driven and learning-based approaches with traditional simulation applications to accelerate scientific discovery and insight. However, these software combinations and integrations are difficult to achieve due to the challenges of coordinating and deploying heterogeneous software components on diverse and massive platforms. We present the ExaWorks project, which addresses many of these challenges. We developed a workflow Software Development Toolkit (SDK), a curated collection of workflow technologies that can be composed and interoperated through a common interface, engineered following current best practices, and specifically designed to work on HPC platforms. ExaWorks also developed PSI/J, a job management abstraction API, to simplify the construction of portable software components and applications that can be used over various HPC schedulers. The PSI/J API is a minimal interface for submitting and monitoring jobs and their execution state across multiple and commonly used HPC schedulers. We also describe several leading and innovative workflow examples of ExaWorks tools used on DOE leadership platforms. Furthermore, we discuss how our project is working with the workflow community, large computing facilities, and HPC platform vendors to address the requirements of workflows sustainably at the exascale.