Earlier quoted context omitted.
It's worth pointing out that every cloud is the same when it comes to capacity / capacity risk. They all apply a lot of time and effort to figuring out the optimal amount of capacity to order based on track record of both customer demand and supply chain satisfaction. Too much capacity is money spent getting no return, up front capex, ongoing opex, physical space in facilities etc. On cloud scales (averaged out over…
All cloud providers are NOT equal here. Amazon over-provisions and sells the excess capacity as spot instances.
Spot instances exist just to try to turn over-provisions in to not a complete loss. You're at least making some money from your mistake.
edit: You should consider "spot instances" in general to be a failure as far as a cloud provider is concerned. It means you've got your guesses wrong. You always want a buffer zone, but not that much of a buffer zone. The biggest single cost for cloud providers is the per-rack OpEx, the cost of powering, cooling etc.