Amazon Web Services provides Auto Scaling which ensures that you have the correct number of Amazon EC2 instances available to handle the load for your application. It is a web service designed to launch or terminate Amazon EC2 instances automatically based on user-defined policies, schedules, and health checks. It can easily scale in and scale out instances as per defined policies.

Auto-scaling provides features to attach load balancer with it so that traffic gets evenly distributed to instances within auto scaling group. Since newly auto-scaled instances would have to access the same content, so we can provision mounting of EFS on EC2 instances. Using Autoscaling in our architecture, we can achieve:

• Better Fault Tolerance
• High Availability
• Better Cost Management

We can also define metrics and custom scaling policies on our auto scaling groups. Scaling policies defines the policy by which instances will get scaled out or scale in.