Obtainability, Part 1: The Other Half of Scarcity
You went to Spot VMs for the discount and did the homework: checkpoint code, a drain handler, a preemption survived. Then a job sat in Pending for days across three regions and never got a single L4. Scarcity grew a second half. Interruption is losing capacity you have; obtainability is failing to get capacity at all, and you can't checkpoint your way out of a stockout. Part 1 of the series that builds the probe the Compute Fallback Ladder left unbuilt.