Configuration and activation
Railgun is configured in /etc/railgun/railgun.conf (GNU/Linux). The most important directives are wan.port, which specifies the port Railgun listens on, and memcached.servers, a space separated list of host:port Memcached instances for Railgun to utilize. It is also possible to specify the full path to a single socket file for Memcached. Using a socket file is recommended for best performance if your Memcached does not require network communication. Make sure at least one Memcached instance is defined. Full details on the available options can be found in the Railgun Execution docs.
If you will be using Railgun in combination with a website hosted behind the same NAT scheme, then you will also need to configure static IP mapping. In other words, if your website and Railgun node are running behind the same router or firewall, there are extra configuration steps necessary to properly route requests. More details in the Potential problems and common issues section. Contact support for assistance, or you can use the examples in /etc/railgun/railgun-nat.conf to define one yourself.
Railgun requires an activation step before usage. To activate, you will need:
- To update the configuration file with the external IP address or a hostname which resolves to the external IP of your Railgun instance for
activation.public_ip - Your activation token for
activation.token.
You can determine the external IP address of a server with the following command:
By default, Railgun will listen on all interfaces. It is best practice to specify the interface you would like Railgun to use. You can do that by setting the wan.ip option to the IP address of the interface you would like Railgun to listen on. This is especially important if you have a local link IPv6 address, as Railgun will prefer that to an IPv4 address, and may not work as a result.
You can find the Railgun activation token listed on your account home, under
Manage Account > Configurations > Railgun. Details on this page can be found in the Administration documentation. You should add a Railgun on the listing page, if you have not already. It can be named anything you like. After adding a Railgun, the token will be listed on the page and you can toggle the Railgun to On. The token is a 32 character hash of numbers and letters. Copy this hash into the activation.token option in your Railgun configuration file. If your public IP and activation token are properly configured, the first time you start Railgun it will register and download a newly generated SSL certificate to encrypt traffic. To make sure that activation works properly, check your logs for a successful activation response when starting Railgun:
If there is a certificate error in the system log or during startup, ensure that the necessary certificate bundle is installed as described in Preparing the Environment so that Railgun may connect securely back to Cloudflare’s activation servers.
As an example, we are going to use domain port2408.net. The newly generated certificate is signed against the port2408.net domain and our system will automatically set your new port2408.net subdomain to resolve to the IP specified by activation.public_ip. You can use this hostname to test Railgun without enabling the service for all users. For more details, refer to the Testing Railgun section below.
Starting the service
You should start the service in the manner that your operating system recommends. This is likely either by using the init script directly, or by invoking the service command:
After running the init script, there should be an rg-listener process listening on the configured port (2408 by default). You can use netstat to make sure:
Provided that your port is open to Cloudflare traffic, it is time for testing. If you do not see the process running, then there may be an issue with activation or your configuration. The Railgun panic log, which is written to /var/log/railgun/panic.log by default, may contain more information. You can also attempt to start Railgun without the init script to see if any errors are present at start:
Testing Railgun
Once you have configured Railgun, you can test its operation on the Cloudflare dashboard:
- Log in to the Cloudflare dashboard and select your account and domain.
- Go to Speed > Optimization > Other.
- Scroll down to Railgun and select Test.
This will indicate whether a request to your web server uses Railgun.
You can also use the log file to monitor results. By default, Cloudflare only logs errors. For testing, you need to raise the log.level option from 0 to 5 in your Railgun configuration and then restart the service. You can then tail the logs to watch the requests being processed:
Railgun will produce 5xx messages when the rg-listener service is unable to reach the origin web server. It is essential that you check that the route between the Railgun server and the web server is clear before contacting support. The easiest way of checking that is by performing a curl command from the Railgun server to the origin web server. If Railgun and the web server are both run on the same physical server, check that it allows loopback HTTP connections on ports 80 and 443 in its firewall settings. Please ensure the correct port is open and contact support if errors persist.
Going live
It is recommended that you consult the Testing Railgun section before enabling Railgun for all visitors to your site.
When you wish to go live, select the desired Railgun for your domain on the
Configurations page and toggle the switch to On. Railgun may take up to five minutes to fully activate, after which you should see the CF-Railgun HTTP header present in responses from all your active Cloudflare DNS records.