Use your own TLS certificates

Estimated reading time: 2 minutes

All UCP services are exposed using HTTPS, to ensure all communications between clients and UCP are encrypted. By default, this is done using self-signed TLS certificates that are not trusted by client tools like web browsers. So when you try to access UCP, your browser warns that it doesn’t trust UCP or that UCP has an invalid certificate.

invalid certificate

The same happens with other client tools.

$ curl https://ucp.example.org

SSL certificate problem: Invalid certificate chain

You can configure UCP to use your own TLS certificates, so that it is automatically trusted by your browser and client tools.

To ensure minimal impact to your business, you should plan for this change to happen outside business peak hours. Your applications will continue running normally, but existing UCP client certificates will become invalid, so users will have to download new ones to access UCP from the CLI.

Configure UCP to use your own TLS certificates and keys

In the UCP web UI, log in with administrator credentials and navigate to the Admin Settings page.

In the left pane, click Certificates.

Upload your certificates and keys:

  • A ca.pem file with the root CA public certificate.
  • A cert.pem file with the TLS certificate for your domain and any intermediate public certificates, in this order.
  • A key.pem file with TLS private key. Make sure it is not encrypted with a password. Encrypted keys should have ENCRYPTED in the first line.

Finally, click Save for the changes to take effect.

After replacing the TLS certificates, your users won’t be able to authenticate with their old client certificate bundles. Ask your users to go to the UCP web UI and get new client certificate bundles.

If you deployed Docker Trusted Registry, you’ll also need to reconfigure it to trust the new UCP TLS certificates. Learn how to configure DTR.

Certificates and compose

For compose to work correctly in the UCP web UI, when you upload your own certificates, they must contain the IP addresses of the swarm’s nodes, as SANs. Get the IP addresses by using the docker node inspect command. Learn to add SANs to swarm certificates.

If you have stable host names, you can join your nodes by specifying the --advertise-addr option:

docker swarm join ... --advertise-addr node1.com

In this example, the docker node inspect command reports node1.com, instead of the IP address.

Where to go next

Universal Control Plane, UCP, certificate, authentication, tls