What is AutoScaling in AWS?

 

Overview of Autoscaling in AWS

AutoScaling in AWS is the advanced cloud computing feature that provides automatic resource management based on the server’s load. The Resources associated with a server cluster generally scale up and scale down dynamically through mechanisms such as load balancer, AutoScaling groups, Amazon Machine Image (AMI), EC2 Instances, and Snapshots. The AWS AutoScaling feature helps in managing the pick time load in business. In addition, it optimizes performance and cost based upon on-demand requirements. AWS provides the flexibility to configure the threshold value of CPU utilization and any resource utilization level; once the load to the server reaches that threshold, the AWS cloud computes engine automatically enables and provision for scaling up the resources. Similarly, it automatically scales down to the default configuration level if the load is below the threshold.

How does Autoscaling work in AWS?

In AWS, there are multiple entities involved in the process of Autoscaling, which is:- Load Balancer and AMIs are two main components involved in this process. First, you need to create an AMI of your current server; in simpler terms, we can say a template of your current configuration consists of all the system setting and the current website. This you can do in the AMI section of AWS. If we go according to our above scenario and configured autoscaling, your system is prepared for future traffic.

When the traffic would start increasing, the AWS autoscaling service would automatically initiate the launch of another instance with the same configuration of your current server with the help of the AMI of your server.

Then comes the next part, where we need to divide or route our traffic equally among the newly launched instances; the load balancer in AWS would take care of this. Load balancer divides the traffic based on the load over a particular system; they do some internal processes to decide where to route the traffic.

The creation of a new instance solely depends on a set of rules defined by the user who is configuring autoscaling. The rules can be as simple as CPU utilization; for example, you can configure autoscaling when your CPU utilization reaches 70 -80 %, then you want to launch a new instance to handle the traffic. Of course, there can be rules to scale down also.

Autoscaling Components in AWS

There are many components involved in the process of autoscaling, some of them we already named before, like AMI, Load balancers, and there are some others as well.

Components involved in Autoscaling:-

• AMI (Amazon Machine Image)
• Load Balancer
• Snapshot
• EC2 Instance
• Autoscaling groups

There can be more components, but you can say most of the components which can be scaled can be part of Autoscaling.

1. AMI

An AMI is an executable image of your EC2 Instance, which you can use to create new instances. For scaling your resources, you need your new server to have all the configuration of your websites and ready to launch. In AWS, you can achieve this by AMI’s, which is nothing but an identical executable image of a system that you can use to create new images, and AWS would use the same in case of autoscaling to launch new instances.

2. Load Balancer

Creating an instance is just one part of autoscaling; you also need to divide your traffic among the new instances, and the Load Balancer handles that work. A load balancer can automatically identify the traffic over the systems to which it’s connected and can redirect the requests on the basis of rules or in a classic way to the instance with less load. The process of dividing the traffic among the instances we call it load balancing. Load balancers are used to increase the reliability of an application and the efficiency to handle concurrent users.

A load balancer places a very important role in autoscaling. Typically load balancers can be of two types:-

• Classic Load Balancer
• Application Load Balancer

Classic Load Balancer

Classic load balancer follows a very simple approach; it will just distribute the traffic equally to all the instances. It’s very basic, and nowadays, nobody uses a classic load balancer. It could be a good choice for a simple static html page website, but in current scenarios, there are hybrid apps or multi-components and high computation applications which has numerous components dedicated to a particular work.

Application Load Balancer

• The most widely used type of load balancer where the traffic is redirected on the basis of certain simple or complex rules that can be based on “path” or “host” or as user-defined.
• It would be better if we take a scenario of a document processing application.
• Let’s say you have an application based on microservice architecture or monolithic, and the path “/document” is specific to a document processing service and other paths “/reports,” which just shows the reports of the documents get processed and stats about processed data. We can have an autoscaling group for one server, which is responsible for processing the documents and another only to show the reports.
• In application load balancer, you can configure and set rule according to a path that if the path matches “/document,” then redirects to an autoscale group for server 1 or if it matches with path “/reports,” then redirect it to an autoscale group for server 2. Internally one group can have multiple instances, and the load will be distributed in classical form means equally among the instances.

3. Snapshot

The copy of the data you have on your hard drive is typically an image of your storage. The typical difference between a snapshot and AMI is an executable image that can be used to create a new instance, but a snapshot is just a copy of the data you have in your instance. If you have an incremental snapshot of your EC2 instance, then a snapshot would be a copy of those blocks that are modified since the previous snapshot.

4. EC2 (Elastic Compute Cloud) Instance

An EC2 instance is a virtual server in Amazon’s Elastic Compute Cloud (EC2), which is used to deploy your applications on Amazon Web Services (AWS) infrastructure. EC2 service allows you to connect to a virtual server with an authenticate key via SSH connection and allows you to install different components of your application along with your application.

5. Autoscaling group

It is a group of EC2 instances and the core of Amazon EC2 AutoScaling. When you create an AutoScaling group, you have to give information about the subnets and an initial number of instances you want to start with.