Zero-Downtime Deployments on AWS with Blue-Green Releases

Blue-green reduces deployment anxiety for revenue-critical apps. Route traffic gradually with weighted ALB rules.

Database migrations need backward compatibility for at least one release cycle. Expand-contract pattern prevents lockstep failures.

Automate rollback triggers on error rate and latency SLO breaches.

Secrets belong in parameter stores — not env files in images.

Run game days quarterly; teams that only practice deploys on Fridays get burned eventually.