Auto Scaling enables you to dynamically scale your computing capacity up or down to meet the workload of your ECS instances according to scaling policies you specify, and reduces the need of manual provision. It monitors your resources, automatically adds or removes capacity in real time as demands change, so as to guarantee availability and save costs.
When demand spikes, Auto Scaling automatically adds computing resources to the scaling group.
When demand decreases, Auto Scaling automatically releases ECS resources to save costs.
Auto Scaling monitors ECS instances, automatically replaces the unhealthy instances with healthy ones to maintain availability.