not sure, probably either an eks cluster with a job scheduler pod that creates jobs via the batch api. The scheduler pod might be replaced by a lambda. Another possibility is something cooked up with a lambda creating ec2 instances via cdk and the whole thing is kept track by a dynamodb table.

the first one is probably cleaner (though I don't like it, it means that I need the instance to be a kubernetes node, and that comes with a bunch of baggage).