For buyers contracting authority
Choose 48626000 when the purpose of the contract is the clustering layer itself: the software that pools servers for failover, high availability, or hyperconverged infrastructure (HCI). The trigger is the function, not the hardware underneath it. If the deliverable is an operating system scoped to one machine class, the sibling codes apply instead, a PC OS is 48624000, an open-systems OS is 48625000, a real-time OS is 48627000.
The practical signal is resilience. Contracting authorities reach this code when they are standing up or renewing a fault-tolerant data-centre platform, the kind that has to survive a node failure without dropping the service. That is why the visible awards lean towards HCI solutions and high-availability cluster licences rather than single-server software.
One boundary to watch: clustering software is the software layer. The servers and storage arrays it runs on belong under their own hardware codes, and where a single contract bundles the cluster licence with the boxes, set the primary CPV code by whichever element is the dominant purpose of the contract.