Setting up an NGINX Load Balancer

NGINX will be configured as Layer 4 load balancer (TCP) that forwards connections to one of your Rancher nodes.

In this configuration, the load balancer is positioned in front of your nodes. The load balancer can be any host capable of running NGINX.

One caveat: do not use one of your Rancher nodes as the load balancer.

These examples show the load balancer being configured to direct traffic to three Rancher server nodes. If Rancher is installed on an RKE Kubernetes cluster, three nodes are required. If Rancher is installed on a K3s Kubernetes cluster, only two nodes are required.

Install NGINX

Start by installing NGINX on the node you want to use as a load balancer. NGINX has packages available for all known operating systems. The versions tested are 1.14 and 1.15. For help installing NGINX, refer to their install documentation.

The stream module is required, which is present when using the official NGINX packages. Please refer to your OS documentation on how to install and enable the NGINX stream module on your operating system.

Create NGINX Configuration

After installing NGINX, you need to update the NGINX configuration file, nginx.conf, with the IP addresses for your nodes.

1. Copy and paste the code sample below into your favorite text editor. Save it as nginx.conf.

2. From nginx.conf, replace both occurrences (port 80 and port 443) of <IP_NODE_1>, <IP_NODE_2>, and <IP_NODE_3> with the IPs of your nodes.

   Note: See NGINX Documentation: TCP and UDP Load Balancing for all configuration options.

   Example NGINX config

   worker_processes 4;
   worker_rlimit_nofile 40000;
   
   events {
       worker_connections 8192;
   }
   
   stream {
       upstream rancher_servers_http {
           least_conn;
           server <IP_NODE_1>:80 max_fails=3 fail_timeout=5s;
           server <IP_NODE_2>:80 max_fails=3 fail_timeout=5s;
           server <IP_NODE_3>:80 max_fails=3 fail_timeout=5s;
       }
       server {
           listen 80;
           proxy_pass rancher_servers_http;
       }
   
       upstream rancher_servers_https {
           least_conn;
           server <IP_NODE_1>:443 max_fails=3 fail_timeout=5s;
           server <IP_NODE_2>:443 max_fails=3 fail_timeout=5s;
           server <IP_NODE_3>:443 max_fails=3 fail_timeout=5s;
       }
       server {
           listen     443;
           proxy_pass rancher_servers_https;
       }
   
   }

3. Save nginx.conf to your load balancer at the following path: /etc/nginx/nginx.conf.

4. Load the updates to your NGINX configuration by running the following command:

   # nginx -s reload

Option - Run NGINX as Docker container

Instead of installing NGINX as a package on the operating system, you can rather run it as a Docker container. Save the edited Example NGINX config as /etc/nginx.conf and run the following command to launch the NGINX container:

docker run -d --restart=unless-stopped \
  -p 80:80 -p 443:443 \
  -v /etc/nginx.conf:/etc/nginx/nginx.conf \
  nginx:1.14