AWS EC2 Elasticity and Scalability

Elasticity in AWS EC2 ensures that your applications can dynamically adjust to changing demands, providing optimal performance, high availability, and cost efficiency.

Auto Scaling

Autoscaling is a cloud computing feature that automatically adjusts the number of active compute resources based on current demand. This helps applications remain fast and available while using resources and money efficiently. In AWS EC2, autoscaling is typically managed by the AWS Auto Scaling service, which automatically changes the number of EC2 instances based on predefined conditions.

Basic Components of AWS Autoscaling Service:

Auto Scaling Group (ASG):

ASG is a logical group of EC2 instances managed as one unit. It specifies the minimum, maximum, and desired number of instances.

Launch Configuration or Launch template:

It defines the configuration of new instances, including AMI, instance type, key pair, security groups and block device mappings. Launch templates offer more features and flexibility compared to launch configurations.

Scaling Policies:

Scaling policies define the criteria for scaling in and out. Policies can be based on various metrics like CPU utilization, request count and so on.

Features of EC2 Auto Scaling:

Dynamic scaling:

Scale Out: It is the process of automatically adding EC2 instances during periods of high demand to maintain application performance.

Scale In: It reduces the number of EC2 instances during periods of low demand to save costs.

Predictive Scaling:

Predictive scaling uses machine learning to forecast future traffic and scales the EC2 fleet ahead of time.

Scheduled Scaling:

Scheduled Scaling allows you to set scaling actions to occur at specific times, based on predictable traffic patterns.

Health checks and Replacements:

Regularly checks the health of running instances and replaces unhealthy instances to ensure high availability.

Integration with Load Balancers:

ASGs work seamlessly with Amazon Elastic Load Balancing to spread traffic across multiple instances, improving fault tolerance and availability.

Auto Scaling groups can manage traffic spikes during peak times. They ensure performance with varying user loads and can scale compute resources based on job queue length (batch processing loads).

To sum up, EC2 Auto Scaling keeps the right number of instances to manage your application's load, ensuring high availability, cost efficiency, and good performance.