  Scientific discovery increasingly requires executing heterogeneous scientific
workflows on high-performance computing (HPC) platforms. Heterogeneous
workflows contain different types of tasks (e.g., simulation, analysis, and
learning) that need to be mapped, scheduled, and launched on different
computing. That requires a software stack that enables users to code their
workflows and automate resource management and workflow execution. Currently,
there are many workflow technologies with diverse levels of robustness and
capabilities, and users face difficult choices of software that can effectively
and efficiently support their use cases on HPC machines, especially when
considering the latest exascale platforms. We contributed to addressing this
issue by developing the ExaWorks Software Development Kit (SDK). The SDK is a
curated collection of workflow technologies engineered following current best
practices and specifically designed to work on HPC platforms. We present our
experience with (1) curating those technologies, (2) integrating them to
provide users with new capabilities, (3) developing a continuous integration
platform to test the SDK on DOE HPC platforms, (4) designing a dashboard to
publish the results of those tests, and (5) devising an innovative
documentation platform to help users to use those technologies. Our experience
details the requirements and the best practices needed to curate workflow
technologies, and it also serves as a blueprint for the capabilities and
services that DOE will have to offer to support a variety of scientific
heterogeneous workflows on the newly available exascale HPC platforms.
