knative-OCP-311.md

Knative on an OpenShift 3.11 cluster

Developer Preview

IMPORTANT: The functionality introduced by Knative on an OpenShift cluster is developer preview only. Red Hat support is not provided, and this release should not be used in a production environment.

Prerequisites

IMPORTANT: You will need cluster administrator privileges to install and use Knative on an OpenShift cluster.

Supported platform versions

Platform	Supported versions
OpenShift	3.11

Installing Knative on an OpenShift cluster using the script provided

1. Login to the cluster using your admin credentials.

   oc login <admin-credentials>

2. Clone the knative-operators repository.

   git clone https://github.com/openshift-cloud-functions/knative-operators  
   cd knative-operators/   
   git fetch --tags   
   git checkout openshift-v0.2.0   

3. Set the following SSH properties using your OpenShift cluster credentials:

   export KUBE_SSH_USER=<username>
export KUBE_SSH_KEY=<path-to-private-ssh-key>

4. Navigate to the newly cloned repository and run the install.sh script.

   ./etc/scripts/install.sh

NOTE The installation script takes around 20-30 minutes to complete, depending on your system.

5. Once the script starts, you will see the following warning and prompt:

  WARNING: This script will blindly attempt to install OLM, Istio, and Knative on your OpenShift cluster, so if any are already there, hijinks may ensue.

  If your cluster isn't minishift, ensure $KUBE_SSH_KEY and $KUBE_SSH_USER are set  

  Pass -q to disable this warning   

  Enter to continue or Ctrl-C to exit:

6. Press Enter to continue.

Post-installation tasks

Allowing external access to Knative services using a configured hostname.

Your Knative services will not be accessible from outside of the OpenShift cluster by default, however you can enable access by configuring a hostname. This method uses wildcard routes to automatically assign a hostname to Knative services.

1. Find the default routing subdomain of your OpenShift cluster. For more information, see Additional resources.

2. Open the config map for your cluster to edit the Knative serving configuration.

   oc edit configmap config-domain -n knative-serving

3. Replace the default "example.com" with your default routing subdomain.

4. Configure your router to allow wildcard domains.

   oc set env dc/router ROUTER_ALLOW_WILDCARD_ROUTES=true -n default

5. Create a route that forwards wildcard traffic to the knative-ingressgateway.

   NOTE: This route requires one host per namespace that is running Knative services. The format for the host of the route is wildcard.<namespace>.<default-routing-subdomain>.

   To do this, you must create a wildcard yaml file (in our example this is named wildcard-routes.yml) with the following content:

    apiVersion: route.openshift.io/v1
    kind: Route
    metadata:
      name: knative-ingressgateway-wildcard
      namespace: <namespace-running-knative-services>
    spec:
      host: wildcard.<namespace>.<default-routing-subdomain>
      port:
        targetPort: http2
      to:
        kind: Service
        name: knative-ingressgateway
        weight: 100
        wildcardPolicy: Subdomain  

6. Apply the yaml file.

   oc apply -f wildcard-routes.yml

7. Clone the demo repository.

   git clone https://github.com/openshift-cloud-functions/demos.git

8. Deploy the demo application.

   oc apply -f ~/demos/knative-kubecon/serving/010-service.yaml

9. View the domain that was assigned to the application. You can now access the demo application using this domain.

   oc get service.serving.knative.dev/dumpy

Additional resources

• For more information about default routing subdomains, see OpenShift documentation.