Answer may be:

Amazon Auto-scaling is the service offered by AWS which allows us to increase or decrease the capacity of the application on demand depending on the limits we set using Cloudwatch. Auto-scaling not only helps in dealing with the servers by dynamically scaling EC2 capacity up or down but also helps in maintaining availability. It automatically adds instances when the traffic increases or removes the instance when not enough traffic is coming depending on the conditions defined by us. Amazon EC2 scaling also does fleet management and health checks of the EC2 instances.

AWS EC2 Scaling policies

EC2 auto scaling engine offers three types of policies:

• Target tracking scaling.
• Step Scaling.
• Simple Scaling.

Types of  AWS EC2 Scaling:

• Scheduled Scaling.
• Dynamic Scaling.
• Predictive Scaling.

For more details, read the full blog:

All about AWS EC2 Auto Scaling