A load balancer distributes incoming client requests across multiple backend servers. This enhances application availability and scalability by preventing any single server from becoming a bottleneck. Key design considerations include:
- Protocol Support: Determine which network protocols (e.g., HTTP, HTTPS, TCP, UDP) the load balancer needs to handle to effectively route traffic to the appropriate backend services.
- Load Balancing Algorithms: Select an algorithm (e.g., Round Robin, Least Connections, IP Hash) to decide how to distribute requests. The choice depends on factors like server capacity, request type, and desired distribution fairness.
- Health Checks: Implement mechanisms to monitor the health of backend servers. If a server becomes unresponsive, the load balancer should automatically stop sending traffic to it and redirect requests to healthy servers.
- Session Persistence (Sticky Sessions): Decide if requests from the same client should always be directed to the same backend server. This is crucial for applications that maintain user session state on the server.
- Scalability and High Availability: The load balancer itself must be scalable and highly available to avoid becoming a single point of failure. This often involves deploying multiple load balancer instances in an active-passive or active-active configuration.
- SSL Termination: Consider whether the load balancer should handle SSL/TLS encryption and decryption, offloading this processing from backend servers.
Google
Mastercard