#40 Review: AWS Fault Injection Simulator (FIS)

AWS allows us to run applications distributed across EC2 instances and availability zones. By adding load balancers or message queues to the architecture, we can achieve fault tolerance or high availability. But how can we test that our system can survive faults in reality? Assuming an application has five consumers and seven downstream dependencies. What happens if one of them fails? Are all timeouts configured accurately? Are all applications retrying? What happens if the network is slow? So many things can go wrong. It is not possible to understand all consequences upfront. Therefore, a new approach emerged: Chaos Engineering. With chaos engineering, we simulate faults in our systems and observe the consequences. The trick is that we can simulate faults as often as we wish. We don't have to wait for the one day a year where things go horribly wrong. AWS released Fault Injection Simulator (FIS) as a tool to run controlled fault experiments within our AWS accounts.