Problem Statement
What is Blue-Green deployment?
Explanation
Blue-Green deployment maintains two identical production environments: Blue (current production) and Green (new version). Deploy new version to Green environment while Blue serves traffic. After testing Green, switch traffic from Blue to Green instantly via load balancer or DNS. If issues arise, switch back to Blue immediately. This enables zero-downtime deployments and instant rollback.
Process: deploy to Green, test Green thoroughly, switch traffic to Green, keep Blue as backup, use Blue for next deployment. Benefits: zero downtime, instant rollback, full testing before traffic switch, reduced risk. Drawbacks: requires double infrastructure (costly), database migrations complex (must be backward compatible), stateful applications challenging.
Use cases: critical applications requiring zero downtime, high-risk deployments needing quick rollback, applications where gradual rollout not needed. Understanding Blue-Green enables reliable zero-downtime deployments.
