AWS EC2 Auto Scaling
AWS Tutorial: Amazon EC2 Auto Scaling
Welcome to the Amazon EC2 Auto Scaling lesson. Building on our knowledge of Horizontal Scaling, AWS provides a service that performs this scaling automatically!
Why Learn Auto Scaling?
Manual scaling is slow and error-prone. By learning EC2 Auto Scaling, you can automate your infrastructure so that it dynamically grows during traffic peaks and shrinks during quiet periods, maximizing performance and minimizing costs.
Tutorial Overview
In this tutorial, you will learn:
- What Amazon EC2 Auto Scaling is.
- How Auto Scaling Groups (ASG) work.
- How to set minimum, desired, and maximum capacities.
What is Amazon EC2 Auto Scaling?
Amazon EC2 Auto Scaling helps you maintain application availability and allows you to automatically add or remove EC2 instances according to conditions you define. You can use the fleet management features to maintain the health and availability of your fleet.
Auto Scaling Groups (ASG)
An Auto Scaling Group is a logical collection of EC2 instances. Within an ASG, you define rules:
- Minimum Capacity: The absolute minimum number of instances that must be running at all times.
- Desired Capacity: The current target number of instances.
- Maximum Capacity: The absolute maximum number of instances the group is allowed to scale out to (preventing runaway costs).
Dynamic Scaling Policies
You can set up CloudWatch alarms to trigger a scaling event. For example:
- If CPU utilization > 70% for 5 minutes, add 2 instances.
- If CPU utilization < 30% for 5 minutes, remove 1 instance.
This ensures your application is always perfectly sized for the current demand!
Exercise
?In an Auto Scaling Group, what setting dictates the upper limit of instances to prevent runaway costs?