Amazon EMR introduces instance fleets to help lower cost and improve cluster provisioning in AWS GovCloud (US) Regions

Amazon EMR now supports instance fleets: a new way to provision clusters in AWS GovCloud (US) Regions. Instead of specifying an Amazon EC2 availability zone for your Amazon EMR cluster and an Amazon EC2 instance type for an Amazon EMR instance group, you can now provide a list of availability zones and instances, and Amazon EMR will automatically select an optimal combination based on cost and availability.

Source:: Amazon AWS