Platform & DevOps·Placement, resources and the pod lifecycle
you say the workload must land on nodes labelled with the fast disk, and the scheduler filters out everything else.
Node affinity
Also calledaffinity, node selector, placement preference
A workload's own rule about which nodes it wants, expressed against node labels and either required or merely preferred. It attracts, where a taint repels, and the two solve different halves of the same problem. Required rules are the ones that leave workloads permanently pending when the matching nodes are full, which is why preferred is the safer default for anything that would rather run somewhere imperfect than not at all.