Launching Amazon EC2 Instances Using Auto Scaling
Auto Scaling provides you with an option to enable Auto Scaling for one or more EC2 instances by attaching them to your existing Auto Scaling group. After the instances are attached, they become a part of the Auto Scaling group.
If you are aiming to use Auto Scaling, then certain important points must be acknowledged. This particular section helps you to gain the basic information regarding it.
Auto Scaling helps you maintain application availability. Auto Scaling launches and terminates Amazon EC2 instances automatically according to user-defined policies, schedules, and alarms. You can use Auto Scaling to maintain a fleet of AWS EC2 instances that can adjust to any presented load. You can also use Auto Scaling to bring up multiple instances in a group at one time.
Auto Scaling provides you with an option to create Auto Scaling group by specifying an EC2 instance as well as attributes such as minimum, maximum or any chosen number, all having similar characteristics. The Auto Scaling group is the core value of the Auto Scaling service. You can associate Auto Scaling group with a load balancer. You can regulate these groups by assigning metadata to each group in the form of tags.
As the name implies, Auto Scaling responds automatically to changing conditions. All you need to do is specify how it should respond to those changes. For example, you can instruct Auto Scaling to launch an additional instance, whenever CPU usage on one or more existing instance exceeds 60 percent for ten minutes, or you could tell Auto Scaling to terminate half of your website’s instances over the weekend, when you expect traffic to be low.
Auto Scaling can ensure that the instances in your fleet are performing optimally so that your applications continue to run efficiently. Auto Scaling groups can even work across multiple Availability Zones, so that if an Availability Zone becomes unavailable, Auto Scaling will automatically redistribute traffic to applications in a different Availability Zone. With Auto Scaling, you can ensure that you always have at least one healthy instance running.