Blue-green deployment vs kill switches: Choosing a deployment strategy

Blue-green deployment and kill switch are two distinct deployment strategies that offer different approaches to managing application updates and minimizing downtime. Blue-green deployment involves maintaining two identical environments, allowing one to serve live traffic while the other is used for deploying and testing new versions, leading to near-zero downtime and instant rollback capabilities by switching traffic between environments. However, this strategy requires duplicate infrastructure, increasing costs and complexity, particularly with database migrations. On the other hand, the kill switch strategy focuses on rapidly disabling problematic features or applications through embedded control mechanisms, providing immediate response to critical issues without the need for full redeployment. This method is cost-effective and ideal for high-risk releases but may introduce code complexity and does not address underlying deployment issues. Feature flags enhance both strategies by offering granular control over feature activation, allowing for more controlled rollouts in blue-green deployments and serving as distributed kill switches in kill switch deployments. Canary deployment is also mentioned as a gradual rollout strategy for incremental updates, offering real-world performance validation with minimal risk exposure.