Progressive Delivery at Scale: Comparing Blue-Green, Canary, and Feature Flag Strategies in Microservices

Abstract

Progressive delivery techniques reduce risk by limiting blast radius and enabling controlled rollout of changes. This paper provides a comprehensive evaluation of blue-green, canary, and feature-flag-driven delivery strategies in microservices. The study proposes decision criteria based on traffic patterns, statefulness, database migration complexity, and operational maturity. Benchmark results demonstrate that properly instrumented canary and flag-based rollouts yield faster rollback capability and improved release confidence compared to environment-swap models alone.