An AWS Auto Scaling group monitors your applications and automatically adjusts capacity to maintain steady, predictable performance at the lowest possible cost. Using AWS Auto Scaling, it's easy to setup application scaling for multiple resources across multiple services in minutes.
See https://aws.amazon.com/autoscaling for more information.
Given that Sync Service is stateless, it can be deployed easily with AWS Auto Scaling groups. However, there are some important aspects to keep in mind.