Configuring external routes

The application you deployed in the previous section is available via the backend (internal) network. The route created for the example application uses the application name my-nginx-example, the cluster name ocp and the domain name hpecloud.org.

http://my-nginx-example-my-nginx-example.apps.ocp.hpecloud.org

However, it is more likely that you will want users to access applications via the frontend (external) network.

The loadbalancers variable is used to define the internal and external networking configuration. A virtual IP (VIP) is specified for external access to applications, and also for external (frontend) and internal (backend) access to the OCP API. The following loadbalancers definition will be used in the subsequent configuration.

loadbalancers:
  apps:
    vip: 10.15.156.42/24
  frontend:
    vip: 10.15.155.9/24
    interface: ens192
    vrrp_router_id: 51
  frontend:
    vip: 10.15.156.42/24
    interface: ens224
    vrrp_router_id: 51

In this example, we assume the domain name cloudra.local is used for external access to resources and services. The DNS zone used to manage records for this specific cluster is ocp.cloudra.local.

You must configure the DNS resolver used by your external users - the provided playbooks will not do this for you.

• If you want users to be able to access the OpenShift API externally, you must configure api.ocp.cloudra.local so that it resolves to the VIP of the load balancer on the frontend network, in this example: 10.15.156.42.
• For external access to all your applications, you must create a wildcard record in the ocp.cloudra.local domain for *.apps pointing to the same VIP 10.15.156.42.

For the above example, the DNS records would look like:

;
;  Database file ocp.cloudra.local.dns for ocp.cloudra.local zone.

;
;  Zone records
;

api                     A	10.15.156.42
*.apps                  A	10.15.156.42

In the above example, where the DNS service is running on Windows, the file resides at C:\Windows\System32\dns\ocp.cloudra.local.dns.

Now, create an Ingress resource for your sample application. This allows connections from an external client to be routed to your application by connecting to the application DNS name my-nginx-example.apps.ocp.cloudra.local.

$ cat ingress-my-nginx-example.yaml

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: my-nginx-example
  namespace: my-nginx-example
spec:
  rules:
  - host: my-nginx-example.apps.ocp.cloudra.local
    http:
      paths:
      - backend:
          serviceName: my-nginx-example
          servicePort: 8080
        path: /

Apply the ingress definition:

$ oc apply -f ingress-my-nginx-example.yaml

ingress.extensions/my-nginx-example created

Now, when you run oc get routes, you will see that a new route has been created for external access:

$ oc get routes

NAME                     HOST/PORT                                                 PATH   SERVICES           PORT  
my-nginx-example         my-nginx-example-my-nginx-example.apps.ocp.hpecloud.org          my-nginx-example   <all> 
my-nginx-example-rvlhc   my-nginx-example.apps.ocp.cloudra.local                   /      my-nginx-example   8080  

Users can now access the application from the external network using the URL http://my-nginx-example.apps.ocp.cloudra.local/

Figure. Nginx example - frontend network