NGINXLoadBalancers.md

NGINX Load Balancers

Objective

Set up load balancing with NGINX to distribute incoming traffic among multiple servers for improved performance and high availability.

Steps

1. Install Nginx:

   • If you haven't installed Nginx, do so based on your operating system. For example:
     • Ubuntu/Debian: sudo apt-get install nginx
     • CentOS: sudo yum install nginx

2. Configure Application Servers:

   • Set up your application on three backend servers.

     sudo apt-get install docker.io -y
     docker run -d --rm --name web-test-01 -p 8081:8000 crccheck/hello-world
     docker run -d --rm --name web-test-02 -p 8082:8000 crccheck/hello-world
     docker run -d --rm --name web-test-03 -p 8083:8000 crccheck/hello-world

   • Repeat for app_server2 and app_server3.

3. Configure NGINX Load Balancer:

   • Add configuration inside the http block.

         upstream backend_servers {
             server 127.0.0.1:8081;
             server 127.0.0.1:8082;
             server 127.0.0.1:8083;
         }
     
         server {
             listen 80;
             server_name your-domain.com;
     
             location / {
                 proxy_pass http://backend_servers;
                 proxy_set_header Host $host;
                 proxy_set_header X-Real-IP $remote_addr;
                 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                 proxy_set_header X-Forwarded-Proto $scheme;
             }
         }

4. Health Checks (Optional):

   • Implement health checks to ensure servers are available.

         upstream backend_servers {
             server 127.0.0.1:8081 max_fails=3 fail_timeout=30s;
             server 127.0.0.1:8082 max_fails=3 fail_timeout=30s;
             server 127.0.0.1:8083 max_fails=3 fail_timeout=30s;
         }
     
         server {
             listen 80;
             server_name your-domain.com;
             
             location / {
                 proxy_pass http://backend_servers;
                 proxy_set_header Host $host;
                 proxy_set_header X-Real-IP $remote_addr;
                 proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
                 proxy_set_header X-Forwarded-Proto $scheme;
             }
         }

5. Testing:

   • Access your application through the NGINX load balancer URL.

   • Monitor NGINX logs for distribution and check backend server logs for incoming requests.

     echo "127.0.0.1 your-domain.com" | sudo tee /etc/hosts
     sudo nginx -t
     sudo systemctl reload nginx
     

6. Cleanup:

• Remove added configuration from point 3 or 4.