Comparison
Node affinityvsTaint
Node affinity
you say the workload must land on nodes labelled with the fast disk, and the scheduler filters out everything else.
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.
Full entry →Taint
the expensive GPU nodes sat empty because they push away every workload that has not explicitly said it can live there.
A mark on a node that repels workloads unless they carry a matching exception. It is the node's own defence — the node decides what it will not take — and it is how you keep general workloads off special hardware, off control-plane machines and off nodes being drained. The direction is the thing to hold on to: a taint pushes away, and only a toleration lets something through.
Full entry →