We have two instance of the application running on 192.168.1.250:2221 and
192.168.1.250:3331
Requests coming to the nginx server on port 8080 will be forwarded to the two
instances in a round robbin fashion.

Write a nginx configuration nginx.conf

http {
   
    upstream all {
        server 192.168.1.250:2221;
        server 192.168.1.250:3331;
    }

    server {
         listen 8080;
         location / {
              proxy_pass http://all/;
         }
    }

}


events { }

Dockerfile dockerfile

FROM nginx
COPY nginx.conf /etc/nginx/nginx.conf

Write the command

mkdir nginx-load-balancer
cd nginx-load-balancer
nano nginx.conf
nano dockerfile
docker build -t nginxlb .
docker run -d --name nginx-load-balancer -p 8087:8080 nginxlb