Deployment Strategies: Scenario-Based Questions

Blue-green deployments minimize downtime and risk by running two identical environments: one live (blue) and one staged (green). Switching traffic between them enables instant rollback and faster recovery.

🏗️ How It Works

• Blue is the current production version.
• Green is the new version deployed in parallel.
• Traffic is switched to green once validated.
• If issues arise, rollback is as simple as switching traffic back to blue.

🛠️ Components Required

• Load Balancer: Controls traffic routing (e.g., ALB, GCLB, NGINX).
• Environment Duplication: Full infra or container replicas.
• Automation: CI/CD pipeline to manage builds, deployments, and cutover.

📦 Cloud Support

• AWS: ECS/EKS/Beanstalk + CodeDeploy blue-green deployments.
• GCP: GKE + traffic splitting via Istio or L7 Load Balancer.
• Azure: App Services with deployment slots.

✅ Best Practices

• Automate health checks before switching traffic.
• Keep environments truly identical to avoid config drift.
• Enable telemetry for both blue and green for comparison.
• Use DNS TTL management for rollback safety.

🚫 Common Pitfalls

• Uncoordinated database migrations across versions.
• Manual switchovers introducing human error.
• Not cleaning up old environments after switch.

📌 Final Insight

Blue-green deployments offer safety and speed — but demand discipline in environment parity and testing. They’re ideal when you need zero-downtime releases and quick rollback capabilities.