Can someone explain the pros and cons of Canary deployments vs Blue-Green deployments?

All answers to this question.

For Kubernetes with Istio, Canary deployments are usually the superior choice. Blue-Green is simpler—you have two identical environments and flip the switch—but it’s expensive because you’re essentially paying for double the infrastructure. Canary releases allow you to route 5% of traffic to the new version and monitor telemetry in real-time. If the error rate spikes, Istio can automatically roll back the traffic. This provides a much higher level of confidence for high-traffic apps. Blue-Green is better if your app isn't built for versioned traffic or has strict database schema requirements.

   Answered 2024-01-08 by Elizabeth Clark

Does your application support session affinity, or will users have issues if they are bounced between the old and new versions during a Canary rollout?

   Answered 2024-01-10 by Michael Brown

• We do use session affinity via sticky cookies. My concern is whether the database can handle two different versions of the code hitting it simultaneously. Have you dealt with backward-compatible migrations during a 10% Canary rollout? That seems to be the biggest technical hurdle for us.

     Commented 2024-01-12 by Kevin Harris

Blue-Green is definitely the safer bet if you don't have advanced monitoring in place yet. It's a simple "all or nothing" approach that is very easy to revert.

   Answered 2024-01-14 by Barbara Martinez

• Agreed, Barbara. If the team is new to Istio, starting with Blue-Green builds foundational confidence before moving to the complexity of Canary.

     Commented 2024-01-15 by Patricia Lewis