When your cluster is provisioned, an AWS elastic load balancer (ELB) is created
to route application traffic into the cluster. The domain for your ELB is
configured to route application traffic via
http(s)://*.<cluster-id>.<shard-id>.p1.openshiftapps.com. The <shard-id> is a
random four-character string assigned to your cluster at creation time.
If you want to use custom domain names for your application routes, {product-title} supports
CNAME records in your DNS configuration that point to
elb.apps.<cluster-id>.<shard-id>.p1.openshiftapps.com. While elb is recommended as a
reminder for where this record is pointing, you can use any string for this
value. You can create these CNAME records for each custom route you have, or you
can create a wildcard CNAME record. For example:
*.openshift.example.com CNAME elb.apps.my-example.a1b2.p1.openshiftapps.com
This allows you to create routes like app1.openshift.example.com and app2.openshift.example.com without having to update your DNS every time.