Get started with Keyless SSL
Before you begin
Keyless has been tested on
arm architectures. The key server binary will likely run on all architectures that Go supports. Code support may exist for other CPUs too, but these other architectures have not been tested.
In addition to running on bare metal, the key server should run without issue in a virtualized or containerized environment. Care will need to be taken to configure ingress access to the appropriate TCP port and file system access to private keys (if using filesystem storage).
Supported operating systems
You will need to be running a supported operating system (OS) to run Keyless. Supported operating systems include:
- Ubuntu 12.04.5 LTS, 14.04 LTS, 15.10, 16.04, 17.10
- Debian 7, 8, 9
- RHEL and CentOS 6, 7
- Amazon Linux 1, 2
We strongly recommend that you use an operating system still supported by the vendor (still receiving security updates) as your key server will have access to your private keys.
Step 1 — Create a public DNS record
You need to create a public DNS record for your key server. If you are using Cloudflare, this record cannot be proxied (orange clouded). As a security measure, you should hide the hostname of your key server.
openssl rand -hex 24to generate a long, random hostname such as
- Add this record via your DNS provider’s interface as an A or AAAA record pointing to the IP address of your Keyless SSL server.
- Use this hostname as the server hostname during initialization of your Keyless SSL server.
Step 2 — Upload “Keyless” SSL Certificates
Before your key servers can be configured, you must next upload the corresponding SSL certificates to Cloudflare’s edge. During TLS termination, Cloudflare will present these certificates to connecting browsers and then (for non-resumed sessions) communicate with the specified key server to complete the handshake.
Upload certificates to Cloudflare with only SANs that you wish to use with Cloudflare Keyless SSL. All Keyless SSL hostnames must be proxied on Cloudflare (orange clouded).
For each certificate you wish to use with Keyless SSL:
- Log in to the and select your zone.
- Navigate to SSL/TLS > Edge Certificates.
- Click Upload Keyless SSL Certificate.
- Fill in the upload modal with the certificate and other details and click Add.
Step 3 — Set up and activate key server
Finally, you need to install the key server on your infrastructure, populate it with the SSL keys of the certificates you wish to use to terminate TLS at Cloudflare’s edge, and activate the key server so it can be mutually authenticated.
- Add the Cloudflare Package Repository as per .
- Amazon Linux customers need to manually set the yum
- Amazon Linux 1:
sudo sed -i 's/$releasever/6/' /etc/yum.repos.d/cloudflare.repo
- Amazon Linux 2:
sudo sed -i 's/$releasever/7/' /etc/yum.repos.d/cloudflare.repo
- Update your OS’ package listings, e.g.,
- Install the gokeyless server (min version used should be 1.5.3):
sudo apt-get install gokeyless
sudo yum install gokeyless
- Amazon Linux:
sudo yum install rsyslog shadow-utils && sudo yum install gokeyless
Add your Cloudflare account details to the configuration file located at
- Set the hostname of the key server, for example,
- Set the Zone ID (found on Overview tab of the Cloudflare dashboard).
Install your private keys in
/etc/keyless/keys/ and set the user and group to keyless with 400 permissions. Keys must be in PEM or DER format and have an extension of
$ ls -l /etc/keyless/keys-r-------- 1 keyless keyless 1675 Nov 18 16:44 example.com.key
When running multiple key servers, make sure all required keys are distributed to each key server. Customers typically will either use a configuration management tool such as Salt or Puppet to distribute keys or mount
/etc/keyless/keys to a network location accessible only by your key servers. Keys are read on boot into memory, so a network path must be accessible during the gokeyless process start/restart.
To activate, restart your keyless instance:
sudo service gokeyless restart
sudo /etc/init.d/gokeyless restart
Allow incoming connections from Cloudflare
During TLS handshakes, Cloudflare’s keyless client will initiate connections to the key server hostname or IP address you specify during certificate upload. By default, the keyless client will use a destination TCP port of 2407, but this can be changed during certificate upload or by editing the certificate details after upload.
Create firewall rules that allow your key server to accept connections from only Cloudflare. We publish our IPv4 and IPv6 addresses via our API.