Intent

EC2 is part of the AWS Elastic Compute Cloud, which acquires and releases resources depending on the traffic demand. Check whether your application is elastic as well by rebooting an EC2 instance.

Motivation

Depending on your traffic demand, you can leverage the ability to acquire and release resources automatically in the AWS cloud. Some services, such as S3 and SQS, do that automatically, while others, such as EC2, integrate with AWS Auto Scaling. Once configured, it boils down to a fluctuating number of EC2 instances starting up or shutting down frequently. Even when not using AWS Autoscaling, your EC2 instances may need to be restarted from time to time for maintenance and updating purposes. Thus it is best practice to validate your application's behavior for that.

Structure

We ensure that a load-balanced user-facing endpoint fully works while having all EC2 instances available. While restarting an EC2 instance, the HTTP endpoint continues operating but may suffer from degraded performance (e.g., lower success rate or higher response time). The performance should recover to a 100% success rate as soon as all EC2 instances are back.

Environment Example

The Kubernetes deployment gateway consists of two pods deployed on two different EC2 instances. We validate whether an exposed HTTP endpoint works with a success rate of at least 95% while restarting one of the EC2 instances.

Solution Sketch

AWS Well-Architected Framework Kubernetes liveness, readiness, and startup probes