Can I use only 2 servers for nginx load balancing?

Question

If I have only 2 servers, can I make each as a backend and also front end?

Server 1: master load balancer / backend server1 Server 2: slave load balancer / backend server2

is it possible?

Answer 1

Yes, it's possible and pretty easy to get it done. Check the nginx wiki. You can bind the "webserver" part on a different port than 80 and the load balancer (or proxy if is the case) on port 80. Use something like this:

loadb vhost

upstream app {
   server 192.168.1.2:81;
   server 192.168.1.3:81;
}
server {
   listen 80;
   // all the usual bla bla
   location / {
       proxy_pass http://app;
   }
}

use the webserver vhost like a default one, just with "listen 81" instead of "listen 80". This is untested, I just copied few of the lines from my config that is running only as a proxy and the backend servers are on different machines... but it should work without any problem.

If you also want to load balance between those 2 proxies, try ultramonkey in front of the nginx and all your requests will distributed equal to both servers (or you can do it with nginx)