2.1What Is a Canary Deployment?

A canary deployment routes a small percentage of production traffic to the new version while the old version serves the rest. Unlike feature flags (which control features at the application level), canary deployments control at the infrastructure level -- the user does not know they are hitting a different version.

The name comes from the "canary in a coal mine" -- a small group of users acts as an early warning system. If the canary version shows degraded metrics, traffic is shifted back to the stable version before most users are affected.