Add PurchasingOption: spot-with-timeout-to-on-demand

[elgalu]

Would it be possible (or maybe it is already) to add a PurchasingOption, let's say called something like spot-with-timeout-to-on-demand that first tries to get a spot instance and then, after certain configurable timeout, it falls-back to on-demand?

[pauloestrela]

When you ask for an amount of EC2 instances through CreateFleet API, you must specify the DefaultTargetCapacityType parameter as spot or on-demand. What can be done is: if an error is raised, repeat EC2 request changing DefaultTargetCapacityType to on-demand. But you can also create 2 partitions, 1 spot em 1 on-demand and a script to move a job that isn't getting a ec2 to the on-demand partition.

https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ec2.html#EC2.Client.create_fleet