Overview

EC2 Auto Scaling helps ensure you have the right number of servers running at any given time. Instead of manually adding or removing servers as your application's workload changes, Auto Scaling does this automatically based on rules you define.

For example, if your website suddenly gets more visitors, Auto Scaling can automatically launch new servers to handle the increased traffic. When the traffic decreases, it can remove unnecessary servers to save costs. This process happens automatically, 24/7, without any manual intervention.

You define the minimum and maximum number of servers you want to run, and Auto Scaling maintains your application's performance by keeping the server count within these bounds. It also automatically replaces any unhealthy servers, ensuring your application remains reliable.

The service continuously monitors your applications using metrics like CPU usage, network traffic, or custom metrics you define. Based on these measurements, it makes decisions about when to add or remove servers.

Example uses

Web Applications: Automatically scale the number of web servers based on visitor traffic throughout the day.
Batch Processing: Add more processing servers during peak job times and remove them when the work is complete.
Scheduled Scaling: Increase capacity during known busy periods (like business hours) and decrease during quiet times.
Cost Optimization: Maintain performance while minimizing costs by only running the servers you need.

Integration with other AWS services

Auto Scaling works seamlessly with several AWS services:

Amazon CloudWatch: Monitor metrics to determine when to scale
Elastic Load Balancing: Automatically distribute traffic across all your servers
Amazon SNS: Send notifications when scaling events occur
AWS CloudFormation: Define your Auto Scaling configuration as code

Think of EC2 Auto Scaling as a smart assistant that ensures your application always has the right amount of computing power, while helping you avoid paying for unused resources.

Amazon EC2 Auto Scaling