Understanding the default ingress certificate

By default OpenShift Container Platform uses the Ingress Operator to create an internal CA and issue a wildcard certificate that is valid for applications under the .apps sub-domain. Both the web console and CLI use this certificate as well.

The internal infrastructure CA certificates are self-signed. While this process might be perceived as bad practice by some security or PKI teams, any risk here is minimal. The only clients that implicitly trust these certificates are other components within the cluster. Replacing the default wildcard certificate with one that is issued by a public or organizational CA will allow external clients to connect securely to applications running under the .apps sub-domain.

Replacing the default ingress certificate

You can replace the default ingress certificate for all applications under the .apps subdomain. After you replace the certificate, all applications, including the web console and CLI, will have encryption provided by specified certificate.

Prerequisites
  • You must have a wildcard certificate and its private key, both in the PEM format, for use.

  • The certificate must have a subjectAltName extension of *apps.<clustername>.<domain>.

Procedure
  1. Create a secret that contains the wildcard certificate and key:

    $ oc create secret tls <certificate> \(1)
         --cert=</path/to/cert.crt> \(2)
         --key=</path/to/cert.key> \(3)
         -n openshift-ingress
    1 <certificate> is the name of the secret that will contain the certificate and private key.
    2 </path/to/cert.crt> is the path to the certificate on your local file system.
    3 </path/to/cert.key> is the path to the private key associated with this certificate.
  2. Update the ingress controller configuration with the newly created secret:

    $ oc patch ingresscontroller.operator default \
         --type=merge -p \
         '{"spec":{"defaultCertificate": {"name": "<certificate>"}}}' \(1)
         -n openshift-ingress-operator
    1 Replace <certificate> with the name used for the secret in the previous step.