Simulating partial failures with AWS Fault Injection Service

This article explains how to simulate partial failures in distributed systems using AWS Fault Injection Service (FIS), Application Load Balancer (ALB), and AWS Lambda. The solution allows teams to test application resilience without causing complete service disruption.

• Combines AWS FIS with ALB weighted routing to redirect a portion of traffic to a Lambda function
• Enables controlled failure simulation without modifying application code
• Provides automated setup and rollback of failure scenarios
• Allows configurable failure rates and error response types
• Uses CloudFormation template to deploy all necessary resources

The key benefit is the ability to safely test how applications handle degraded conditions by injecting controlled partial failures, helping teams improve system resilience and identify potential weaknesses.