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Auto Scaling in AWS

Auto Scaling
Auto Scaling is a feature in AWS for scaling up or scaling down the number of Amazon EC2 instances.

The Auto Scaling feature can be accessed and configured via the AWS Management Console from the EC2 service page. Auto Scaling can also be configured via the AWS Command Line Interfaces (CLI) or APIs.

Auto Scaling is enabled by CloudWatch and does not carry additional fees. However, there are fees applied to EC2 instance usage and CloudWatch detailed monitoring.

The scenario in which you can use Auto Scaling properly is in which you have an application that can be load balanced. These applications must be able to be dynamically installed or updated after an EC2 instance launch. This would require some sort of scripting e.g. you can use PowerShell Desired State Configuration if you are familiar with it.

You can create your own AMIs (Amazon Machine Image) for every version of your application release, and these AMIs can be used to launch new EC2 instances. In this way, little or no scripting is required to have identical applications on multiple application servers.

Launch Configuration
Auto Scaling is configured by firstly creating a Launch Configuration. You specify a name for this configuration and the AMIs to use for launching EC2 instances along with basic network, storage and security group configurations .

AutoScaling Group
Create an Auto Scaling group for this Launch Configuration. You will need to configure basic network configurations and scaling policies based on CloudWatch alarms that were created. You also (optionally) should specify a load balancer. You can configure Notifications so an administrator gets informed when an instance gets created or terminated or failed to launch or failed to terminate by Auto Scaling.

It should be obvious now that with some careful planning and design of your application, you can make it highly available through the use of load balancers and make it run at maximum performance by launching more application servers when needed and then terminating the servers during off peak or idle periods.

More information on using Auto Scaling is here:

https://aws.amazon.com/autoscaling/getting-started/

My blog on Amazon CloudWatch :

http://networkadministratorsurvivalkit.blogspot.com/2016/08/aws-cloudwatch.html




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