Use a load balancer with Railgun
is a web proxy system that allows dynamic content for a website — such as news sites or personalized content — to be cached while also allowing changes to the site to take effect almost instantly. Railgun is currently available to customers with a Business or Enterprise plan or via one of Cloudflare’s Optimised Partners.
By adding a load balancer to Railgun, you speed up connections between Cloudflare data centers and DNS origin servers so that uncacheable requests have minimal latency.
Set up Railgun in front of a load balancer
We recommend that you put Railgun in front of your load balancer so the load balancer can handle HTTP connections normally. This option provides a much simpler setup because it is difficult to load balancing long-lived TLS connections between the sender and listener.
Use the same load balancer settings as if Railgun were not in place. For example, enable HTTP keep-alive connections and set them to a 90-second timeout, since Railgun is working as an HTTP reverse proxy.
Set up Railgun behind a load balancer
Though Railgun's optimal placing is in front of your load balancer, you can also put Railgun behind a load balancer.
Observe the following guidelines to avoid interruptions with site traffic:
- Use the
railgun-nat.confconfiguration file to set the internal addresses of the hosts Railgun will be optimizing (
localhost:8080, for example). This is important to avoid looping the request outbound to the internet and back to the load balancer only to be forwarded to the origin.
- Ensure no firewall rules are in place that will interfere with traffic between the listener and the origin server.
- Ensure port 2408 is open and passed through the load balancer so that it does not interfere with the TLS connection between the listener and sender.