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NGINX Load Balancing

First off you will need a debian10 server to run nginx as a load balancer, and 2 other http servers.

Initial Setup

First we're go install nginx:

apt update -y && apt upgrade -y
apt install nginx -y
	

Then you will need 2 http servers (mine are 192.168.0.150:80 and 192.168.0.151:80):

Then make the configuration to load balance the 2 servers:

nano /etc/nginx/sites-available/loadb.conf

upstream backend {
        server 192.168.0.150:80 weight=1;
        server 192.168.0.151:80 weight=2;

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

Hit CTRL+S to save and CTRL+X to exit nano.

Launching the config

Now remove the default config and launch reload nginx:

rm /etc/nginx/sites-available/default
rm /etc/nginx/sites-enabled/default

ln -s /etc/nginx/sites-available/loadb.conf /etc/nginx/sites-enabled/loadb.conf
nginx -s reload

And test if it load balances well. It should give us the output of the .151 server because it has the highest weight:

As you can see, nginx determines the number of allowed requests to each load balanced website with the weight parameter, for instance, our .151 server has a weight of 2, so nginx will allow us 2 requests before switching back to the .150 server.

This is also possible with other ports like database servers:

upstream sqlbackend {
        server 192.168.0.150:3386 weight=1;
        server 192.168.0.151:3386 weight=2;

}
server {
        listen 3386;
        listen [::]:3386;
        location / {
                proxy_pass sqlbackend;
        }
}
	

It is also possible to do with UDP:

stream {
upstream ntp {
        server 192.168.0.150:123 weight=2;
        server 192.168.0.151:123 weight=3;

}
server {
        listen 123 udp;
        listen [::]:123 udp;
        location / {
                proxy_pass ntp;
        }
}
}

Here you can see how flexible nginx truly is, it can handle load balancing of multiple types of services, apply weights parameters over tcp/udp services.

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