Load balancer (Networking)

Load balancing across multiple application instances is a commonly used technique for optimizing resource utilization, maximizing throughput, reducing latency, and ensuring fault‑tolerant configurations.

Load balancing in Nginx is configured using upstream directive.. Supported load balancer algorithms: Round Robin, Least Connections, IP Hash, Generic Hash, Least Time (Nginx Plus), Random

Network load balancer can provide service for different protocols, such as TCP, UDP, HTTP or HTTPS.

Typical options:

• Listening port
• FQDN
• Protocol: TCP, UDP, HTTP, HTTPS, Websockets
• Destination servers and destination port
• Load Balancing algorithm: WRR, weighted least connection, source IP hash
• Sticky session

Nginx configuration example

upstream backend {
    server backend1.example.com slow_start=30s;
    server backend2.example.com;
    server 192.0.0.1 backup;
}

Related terms

• Amazon Elastic Load Balancer (ELB)
• Load Balancer as a Service (LBaaS)

See also

• HTTP, HTTP client, HTTP/1.1, HTTP/2, HTTP/3, HTTPS, HSTS CSR, TLS, SSL, openSSL, WebSockets, WebRTC, ssl_certificate QUIC, HPKP, CT, List of HTTP status codes, URL redirection, Content-type:, Webhook, HTTP headers, --insecure, Axios HTTP client, HTTP cookies, HTTP ETag
• Proxy servers: Squid, Reverse proxy, Nginx, HAProxy, Varnish, Load balancer, Load Balancer as a Service (LBaaS), Symantec proxySG and Advanced Secure Gateway (ASG), Traefik, tinyproxy, Proxyrack, Luminati Networks, SOCKS, Envoy Proxy
• Traefik

https://docs.nginx.com/nginx/admin-guide/load-balancer/http-load-balancer/#overview