ECS Capacity Providers

• Capacity Providers determine the infrastructure to use for your task
• The capacity provider strategy determines how the tasks are spread across the capacity providers
• allows the application to define its requirements for how it uses the capacity

Fargate

• Fargate spot uses spare compute capacity and provides up to 70% savings compared to Fargate
• When AWS needs the capacity back, your tasks will be interrupted with a two-minute warning
• With Fargate Spot you can run interruption tolerant Amazon ECS tasks at a fraction of the cost
• if no launch type or capacity provider strategy is set, services will get deployed using the default mix of Fargate and Fargate spot
• Spot tasks can be terminated at any time when capacity requirements change

EC2

• enable customers to use Cluster Auto Scaling, allowing the focus of the customer to shift from managing autoscaling the backend infrastructure
• customers can also spread their tasks across different Auto Scaling groups
• The capacity provider assigned to the cluster will recognize that the target capacity of the total cluster resources is above 80%. This will trigger an autoscaling event to scale EC2 to get the capacity back to 80% or under.

EC2 Spot

• spare EC2 capacity offered with an up to 90% discount compared to On-Demand pricing
• optimize your compute costs on the AWS cloud and scale your application’s throughput up to 10X for the same budget
• Spot Instances can be interrupted with a two minutes warning when EC2 needs the capacity back
• When a container instance is set to DRAINING, Amazon ECS prevents new tasks from being scheduled for placement on the container instance.
• A Spot capacity pool is a set of unused EC2 instances with the same instance type
• By using the capacity-optimized SpotAllocationStrategy, EC2 Auto Scaling launches instances from the pools with optimal capacity for the number of instances that are launching, making use of real-time capacity data
• setting up the Auto Scaling group to launch only EC2 Spot Instances and using the capacity-optimized Spot Allocation Strategy makes Auto Scaling launch instances from the Spot capacity pool with optimal capacity for the number or instances that are launching
• recommended that you combine instances of the same size when creating an Auto Scaling group for ECS for predictable scaling behavior

Base Value

• how many tasks, at a minimum, to run on the specified capacity provider
• Only one capacity provider in a capacity provider strategy can have a base defined

Weight value

• the relative percentage of the total number of launched tasks that should use the specified capacity provider