Hardware Management for Liquid Cooling: Enabling Efficient Operations in Immersion Solutions

Author: Jeff Otter (HPE, Co-chair OCP Hardware Management Sub-Project, Co-chair DMTF Redfish Forum); John Leang (OCP Steering Committee Representative for Hardware Management) Collection: 2023 Global Summit - Cooling Environments

Summary

This presentation reported on the OCP Hardware Management workstream's completion of a unified Redfish data model for liquid cooling equipment, published by the DMTF as Redfish Release 2023.1 in April 2023 and subsequently updated in Release 2023.2. The core problem being solved is that liquid cooling equipment — CDUs, immersion tanks, cold plates, rear-door heat exchangers — has historically been managed through proprietary vendor protocols, creating a fragmented operational landscape where each vendor's equipment requires custom software integration. The Redfish standard, a RESTful (HTTP-based) JSON interface already dominant in compute management since its initial 2015 release, needed to be extended to cover the full liquid cooling stack so that data center operators could use the same tools and APIs for cooling infrastructure that they already use for servers and storage.

Jeff Otter (HPE) explained the practical value of the RESTful approach: unlike older binary protocols with fixed-offset encodings, Redfish data is human-readable JSON accessible via standard web tooling. Any engineer can parse Redfish responses and understand the data structure with 20–30 minutes of exploration, a standard web services reference, or a short YouTube tutorial. The DMTF had been working on data center peripheral management since 2017, including a formal alliance partnership with ASHRAE formed that year to align property naming and measurement definitions for facility-level equipment (CRAC units, PDUs, etc.). When liquid cooling equipment began integrating physically into racks and directly onto servers, it was a natural extension of that work.

The workstream produced three key deliverables: (1) a unified Redfish data model covering CDUs, immersion tanks, cold plates, rear-door heat exchangers, chassis, cooling loops, pumps, reservoirs, filters, and leak detection subsystems — approximately 80% of the required model, ratified in Release 2023.1; (2) JSON mockup examples (published on GitHub at opencomputeproject/HWMgmt-OCP-Profiles) showing what compliant implementations look like; and (3) an OCP Interoperability Profile — a machine-readable specification that defines which Redfish properties are required, recommended, or optional for each equipment type (CDU, Immersion Tank, Enclosed Chassis, Cold Plate). The profile works with Redfish's open-source validator to auto-generate compliance test runs that produce pass/fail reports.