purchaseOption
Specifies how EC2 instances are purchased on your behalf. PCS supports On-Demand Instances, Spot Instances, and Amazon EC2 Capacity Blocks for ML. For more information, see Amazon EC2 billing and purchasing options in the Amazon Elastic Compute Cloud User Guide. For more information about PCS support for Capacity Blocks, see Using Amazon EC2 Capacity Blocks for ML with PCS in the PCS User Guide. If you don't provide this option, it defaults to On-Demand.