Deploy Blazor Server applications on Amazon ECS with AWS Fargate

This article provides a comprehensive guide to deploying Blazor Server applications on Amazon ECS with AWS Fargate, addressing the unique infrastructure requirements of stateful Blazor Server circuits.

• Blazor Server maintains persistent WebSocket connections and in-memory circuits requiring sticky session routing to a single container instance
• Configure target group cookie stickiness to bind browsers to specific Fargate tasks using awsvpc networking
• Align timeout settings across CloudFront (60s OriginReadTimeout), load balancer (60s idle), and SignalR (15s keep-alive) to maintain WebSocket connections
• Use CloudFront VPC origin to expose internal Application Load Balancer as the only public endpoint
• Set deregistration delay to 60 seconds and ShutdownTimeout below StopTimeout to gracefully drain in-flight requests during deployments
• Store session state in external services like RDS PostgreSQL or ElastiCache Redis to survive task replacement
• Configure Data Protection with AWS Systems Manager Parameter Store for shared encryption keys across multiple instances
• Complete AWS CDK stack provided in C# for VPC, ECS cluster, Fargate service, ALB, and CloudFront distribution

Proper infrastructure configuration enables Blazor Server deployments on Fargate while maintaining session continuity and graceful handling of task lifecycle events.