A Spot Instance uses spare EC2 capacity that is available for less than the On-Demand price. Because Spot Instances enable you to request unused EC2 instances at steep discounts, you can lower your Amazon EC2 costs significantly. The hourly price for a Spot Instance is called a Spot price. The spot price of each instance type in each Availability Zone is set by Amazon EC2, and is adjusted gradually based on the long-term supply of and demand for Spot Instances. Your Spot Instance runs whenever capacity is available.s
Spot Instances are a good fit for stateless, fault-tolerant, and flexible applications. These include batch and machine learning training workloads, big data ETLs such as Apache Spark, queue processing applications, and stateless API endpoints.
Because Spot is spare Amazon EC2 capacity, which can change over time, we recommend that you use Spot capacity for interruption-tolerant workloads. More specifically, Spot capacity is suitable for workloads that can tolerate periods where the required capacity isn’t available.