How Amazon ECS Deployment Circuit Breaker Automatically Detects and Rolls Back Failures

Amazon ECS includes a deployment circuit breaker that monitors service health during updates and automatically rolls back if critical failures are detected. The feature tracks container health checks, load balancer target group health, and overall service stability throughout the deployment process. A rollback is triggered when newly deployed tasks repeatedly fail health checks, when unhealthy tasks cause the running count to drop below the configured minimumHealthyPercent threshold, or when the deployment stalls entirely. Users must explicitly enable the circuit breaker in their service's deployment configuration alongside settings like maximumPercent and minimumHealthyPercent. Once a failure is detected, ECS halts the deployment, terminates unhealthy new tasks, and allows the existing healthy tasks to continue serving traffic.