Deployment

It is important to note that Blazor Server operates as a stateful service, where all session data is maintained in the server's memory. In scenarios with multiple users, horizontal scaling may become necessary. Since Blazor utilizes persistent WebSocket connections, the scaling infrastructure must be capable of maintaining these connections and correctly routing messages to the appropriate instances that manage the user sessions. Additionally, the system must handle reconnection logic to ensure session continuity when disruptions occur.

Session Affinity

Session affinity, or "sticky sessions," is a crucial routing mechanism in Stateful server-side applications that ensures all requests from a specific user are consistently directed to the same server instance, particularly when scaling out.

Session affinity guarantees that all SignalR messages are routed to the same instance. This approach also automatically manages reconnections when necessary.

The following diagram outlines the services that offer WebSockets session affinity, along with the deployment options for scalable back-end infrastructure across the major cloud providers (AWS, Azure, GCP). Service selection should be driven by your specific technical requirements:

Deployment options