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An Auto Scaling group contains a collection of EC2 instances that share similar characteristics and are treated as a logical group for the purposes of instance scaling and management. For example, if a single application operates across multiple instances, you may prefer to increase the number of instances in that group to improve the performance of the application or decrease the number of instances to reduce costs when demand is low.

You can use the Auto Scaling group to scale the number of instances automatically based on criteria that you specify, or maintain a fixed number of instances even if an instance becomes unhealthy. This automatic scaling and maintaining the number of instances in an Auto Scaling group is the core functionality of the Amazon EC2 Auto Scaling service.

AWS EC2 Auto Scaling based on a CloudRanger schedule allows you to scale your application in response to predictable load changes. For example, if the traffic to your web application consistently increases on Wednesday, remains high on Thursday, and starts to decrease on Friday, you can use CloudRanger scheduled Auto Scaling to automatically increase or decrease capacity to match the predictable traffic patterns of your web application.

AWS EC2 Auto Scaling allows you to automatically scale your EC2 resources based on predictable demand. The minimum, maximum, and desired values of an Auto Scaling Group (ASG) are the boundaries within which your scaling is confined. CloudRanger Auto Scaling schedules allow you to adjust these parameters in a fully automated manner. A Cloudranger Autoscaling group schedule sets the minimum, maximum, and desired values of an Auto Scaling Group (ASG) at the specified time when the schedule runs.

If at schedule run time the number of servers was outside the limit, AWS would automatically create or terminate servers depending on the new limit set at that time. Below is an example of how CloudRanger affects the ASG.

ASG values prior to the CloudRanger scheduled run

ASG values set in CloudRanger Schedule

​ASG values post the Cloudranger schedule run

For more information on how to configure such scheduels in CloudRanger, see Server Scheduling for Auto-Scaling Groups.