Blue-Green Deployment

You might say

Keep blue serving while deploying and accepting the new release on green; switch production traffic only after it passes.

Blue-green deployment runs old and new releases in two production-capable environments, then switches traffic after the candidate environment is verified.Blue can keep travel site v1 live while green independently runs v2; after login and booking checks pass, the production entry switches to green and blue remains temporarily available for return. Two application environments do not automatically isolate or make the database compatible.

Know first

Deployment Staging

Blue-Green DeploymentBlue/Green Deployment

How production traffic switches from blue to green

PRODUCTION ENTRYtravel.example.com

100% → BLUE

↓ 100%0%

BLUEv1.8.4

Hangzhou weekendLogin healthy · Booking healthy

Serving production

GREENv2.0.0

Waiting for v2No production traffic

Independent candidate

Blue v1 stays live, so deploying v2 does not overwrite the serving application in place.

What two environments solve

The candidate does not overwrite the serving release in place: While blue keeps v1 live, the team deploys and checks v2 in an independent green environment. A failed green does not overwrite blue; the production entry changes only after login, booking, and health checks pass.

Verify after switching and keep a return path: After routing to green, confirm the live version and key signals. Retain blue temporarily so traffic can return on anomaly. The observation period, resource cost, and data compatibility determine when the old environment can be removed.

Quick checkChoose the best answer

Green v2 passes page checks, but it applies a database change that old blue v1 cannot read. What should happen now?

Resolve forward and backward data compatibility and the recovery plan before switching production trafficSwitch immediately because blue-green guarantees rollbackDelete blue before switching to avoid running two environments

You can say this to an AI Agent

Blue-green deploy travel site v2: keep blue v1 serving production while deploying and verifying login and booking on green. Check data compatibility before switching traffic; afterward confirm the live version, error rate, and booking success, and temporarily retain blue for return.

Learn next

1Rollback→2Monitoring→3Canary Release→