How to configure Nginx to load balance traffic across multiple backend servers?

To configure Nginx to load balance traffic across multiple backend servers, you can follow these steps:

Install Nginx: Install Nginx on your server if it is not already installed. You can use the package manager specific to your operating system or download the source code from the Nginx website.
Create an Nginx configuration file: Create a new configuration file for your load balancer. Typically, Nginx configuration files are located in the /etc/nginx directory. You can create a new file with a name like load-balancer.conf.
Configure upstream servers: Define the backend servers in the configuration file using the upstream directive. Specify the IP address or hostname of each backend server and assign weights to distribute traffic unevenly if desired. Example:

http {
  upstream backend {
    server backend1.example.com weight=3;
    server backend2.example.com;
    server backend3.example.com;
  }
}

Define a server block for load balancing: Create a server block in your configuration file to define the load balancer. Specify a listening port and the location that should be load balanced. Example:

server {
  listen 80;
  
  location / {
    proxy_pass http://backend;
  }
}

Adjust other configuration settings: Configure other settings based on your needs. For example, you can set the load balancing algorithm, enable health checks, or adjust timeouts.
Test the configuration: Before applying the configuration, use the nginx -t command to test the syntax of your configuration file. This will ensure that there are no syntax errors.
Apply the configuration: If the configuration test is successful, apply the new configuration by reloading Nginx using the command nginx -s reload.

After applying these steps, Nginx will start load balancing traffic across your backend servers based on the defined configuration.