Code-Memo

Load balancing a commonly used technique for optimizing resource utilization, maximizing throughput, reducing latency, and ensuring fault‑tolerant configurations. It involves distributing client requests across multiple servers to ensure no single server becomes a bottleneck.

Basic Configuration

To set up load balancing in Nginx, you’ll need to configure it in the nginx.conf file or within a specific server block. The configuration involves defining an upstream block and specifying how requests should be distributed.

http {
    upstream myapp {
        server backend1.example.com;
        server backend2.example.com;
        server backend3.example.com;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://myapp;
        }
    }
}

In this example:

• The upstream block defines a group of backend servers (backend1, backend2, backend3).
• The proxy_pass directive in the location block forwards requests to the upstream group.

Load Balancing Methods

Nginx supports several load balancing algorithms. You can configure these methods using the upstream directive.

Round Robin (Default)

• Distributes requests evenly across all servers.

upstream myapp {
    server backend1.example.com;
    server backend2.example.com;
}

Least Connections

• Routes requests to the server with the fewest active connections.

upstream myapp {
    least_conn;
    server backend1.example.com;
    server backend2.example.com;
}

IP Hash

• Routes requests from the same client IP to the same server, which can help with session persistence.

upstream myapp {
    ip_hash;
    server backend1.example.com;
    server backend2.example.com;
}

Load Balancing with SSL/TLS

You can use Nginx to terminate SSL/TLS connections and then perform load balancing over HTTP. This setup involves configuring SSL/TLS in the server block and proxying requests to the backend servers.

server {
    listen 443 ssl;
    server_name example.com;

    ssl_certificate /path/to/cert.pem;
    ssl_certificate_key /path/to/key.pem;

    location / {
        proxy_pass http://myapp;
    }
}

Quick Notes:

• Use nginx -t to test configuration syntax before applying changes.