Whats the difference on using a ECS capacity provider and using automatic scaling from auto scaling group in a ECS cluster?

Question

I'm not seeing the point in using a capacity provider to scale the ECS cluster if I have automatic scaling at the ECS service level:

https://docs.aws.amazon.com/AmazonECS/latest/developerguide/service-auto-scaling.html

Am I missing something? Why would I use a capacity provider to scale the auto scaling group if I already can scale it at the service level?

Answer 1

Your auto scaling group scaling works on a service level only. An ECS cluster can have many services running. Therefore, capacity provider runs at cluster level and can scale your container instances based on all the services in the cluster, not only one service.