Design and Operation of a Federated GPU Cluster for Digital Humanities within DHinfra.at
We describe the design, implementation, and operation of a small federated GPU cluster built for Digital Humanities (DH) research within the Austrian DHinfra.at project. The system spans two university sites, brokers logins from a national identity federation, and exposes compute through three interfaces: interactive notebooks, SSH, and an OpenAI-compatible inference API. The core of the platform is a control plane that maps federated identity, per-project quotas, and a model catalogue onto self-service interfaces. We document this control plane in detail, including the request-and-approval queue that mediates every privileged cluster effect and the two-tier model-serving setup, which combines always-on services with on-demand model swapping and lets researchers consume large language models over HTTPS without holding a cluster account. We report the constraints that shaped the build: a fixed power budget, EU-wide procurement, a team of about 1.5 full-time equivalents, and the relationship between prioritized access and utilization. We also record the main build decisions against the alternatives we researched and did not adopt. The platform is released under the Apache License 2.0. We close with a playbook for teams building a domain-specific GPU cluster on a limited budget. This is a living technical report, versioned and updated as the platform evolves.