Load Balancing & Traffic Management
The load balancing utilities provide intelligent traffic distribution, failover handling, and performance optimization for edge environments. These utilities help distribute requests across multiple backend services, handle failures gracefully, and optimize response times.Features
- Multiple Algorithms: Round-robin, least connections, weighted, IP hash
- Health Monitoring: Automatic backend health checks and failover
- Load Metrics: Real-time load monitoring and adaptive balancing
- Geographic Routing: Location-based traffic routing
- Performance Optimization: Response time-based load balancing
- Session Affinity: Sticky sessions and connection persistence
- Auto-scaling: Dynamic backend pool management
- Circuit Breaker: Fault tolerance and graceful degradation
Quick Start
Load Balancing Algorithms
Round Robin
Distributes requests sequentially across all healthy backends.Weighted Round Robin
Distributes requests based on backend weights.Least Connections
Routes to the backend with the fewest active connections.IP Hash
Routes requests from the same IP to the same backend (session affinity).Least Response Time
Routes to the backend with the fastest recent response times.Random
Randomly selects a healthy backend.BackendPool
Manages the collection of backend servers with health status and metadata.Constructor Options
Backend Configuration
Dynamic Backend Management
Health Monitoring
Automatic health checks and failure detection for backend servers.Health Check Configuration
Custom Health Checks
Health Status Monitoring
Circuit Breaker Pattern
Prevents cascading failures by temporarily stopping requests to failing backends.Circuit Breaker Configuration
Circuit Breaker States
Session Affinity
Maintains session persistence by routing related requests to the same backend.Sticky Sessions
Session Management
Geographic Load Balancing
Routes traffic based on geographic location for improved performance.Geo-based Routing
Performance Optimization
Connection Pooling
Request Queuing
Load Shedding
Advanced Examples
Multi-region Load Balancing
API Gateway with Load Balancing
Auto-scaling Integration
Blue-Green Deployment
Middleware Integration
Load Balancing Middleware
Performance Considerations
Connection Optimization
Caching Backend Selection
Async Backend Selection
Platform-Specific Notes
Cloudflare Workers
- Use Durable Objects for session affinity
- Leverage Cloudflare’s global network for geo-routing
- Compatible with Cloudflare Load Balancing
Vercel Edge Functions
- Use Vercel’s edge network for geographic routing
- Compatible with Vercel KV for backend state
- Support for Vercel’s deployment regions
Deno Deploy
- Native HTTP/2 support for connection pooling
- Compatible with Deno KV for distributed state
- Support for Web APIs for load balancing
Best Practices
Backend Configuration
Health Check Best Practices
Monitoring and Alerting
Testing
Run load balancing tests with:API Reference
LoadBalancer Methods
selectBackend(request, options)
- Select backend for requestgetMetrics()
- Get load balancer metricsgetHealthStatus()
- Get health status of backendsaddBackend(backend)
- Add backend dynamicallyremoveBackend(backendId)
- Remove backendupdateBackend(backendId, config)
- Update backend configuration
BackendPool Methods
addBackend(backend)
- Add backend to poolremoveBackend(backendId)
- Remove backend from poolupdateBackend(backendId, config)
- Update backend configurationgetBackend(backendId)
- Get backend by IDgetHealthyBackends()
- Get all healthy backendsgetAllBackends()
- Get all backends
HealthChecker Methods
checkBackend(backend)
- Check specific backend healthcheckAllBackends()
- Check all backends healthgetHealthStatus()
- Get health status of all backendson(event, callback)
- Listen for health events
Contributing
When contributing to load balancing utilities:- Maintain backward compatibility
- Add comprehensive tests for new algorithms
- Update documentation for new features
- Consider performance impact of changes
- Test across all supported platforms