Installing Knative Serving - Install | Serverless | OpenShift Container Platform 4.8

Installing Knative Serving by using the web console
Installing Knative Serving by using YAML
Next steps

Installing Knative Serving allows you to create Knative services and functions on your cluster. It also allows you to use additional functionality such as autoscaling and networking options for your applications.

After you install the OpenShift Serverless Operator, you can install Knative Serving by using the default settings, or configure more advanced settings in the KnativeServing custom resource (CR). For more information about configuration options for the KnativeServing CR, see Global configuration.

If you want to use Red Hat OpenShift distributed tracing with OpenShift Serverless, you must install and configure Red Hat OpenShift distributed tracing before you install Knative Serving.

Installing Knative Serving by using the web console

After you install the OpenShift Serverless Operator, install Knative Serving by using the OpenShift Container Platform web console. You can install Knative Serving by using the default settings or configure more advanced settings in the KnativeServing custom resource (CR).

Prerequisites

You have access to an OpenShift Container Platform account with cluster administrator access.
You have logged in to the OpenShift Container Platform web console.
You have installed the OpenShift Serverless Operator.

Procedure

In the Administrator perspective of the OpenShift Container Platform web console, navigate to Operators → Installed Operators.
Check that the Project dropdown at the top of the page is set to Project: knative-serving.
Click Knative Serving in the list of Provided APIs for the OpenShift Serverless Operator to go to the Knative Serving tab.
Click Create Knative Serving.
In the Create Knative Serving page, you can install Knative Serving using the default settings by clicking Create.

You can also modify settings for the Knative Serving installation by editing the KnativeServing object using either the form provided, or by editing the YAML.
- Using the form is recommended for simpler configurations that do not require full control of KnativeServing object creation.
- Editing the YAML is recommended for more complex configurations that require full control of KnativeServing object creation. You can access the YAML by clicking the edit YAML link in the top right of the Create Knative Serving page.
  
  After you complete the form, or have finished modifying the YAML, click Create.
  
  For more information about configuration options for the KnativeServing custom resource definition, see the documentation on Advanced installation configuration options.
After you have installed Knative Serving, the KnativeServing object is created, and you are automatically directed to the Knative Serving tab. You will see the knative-serving custom resource in the list of resources.

Verification

Click on knative-serving custom resource in the Knative Serving tab.
You will be automatically directed to the Knative Serving Overview page.
Scroll down to look at the list of Conditions.
You should see a list of conditions with a status of True, as shown in the example image.

It may take a few seconds for the Knative Serving resources to be created. You can check their status in the Resources tab.
If the conditions have a status of Unknown or False, wait a few moments and then check again after you have confirmed that the resources have been created.

Installing Knative Serving by using YAML

After you install the OpenShift Serverless Operator, you can install Knative Serving by using the default settings, or configure more advanced settings in the KnativeServing custom resource (CR). You can use the following procedure to install Knative Serving by using YAML files and the oc CLI.

Prerequisites

You have access to an OpenShift Container Platform account with cluster administrator access.
You have installed the OpenShift Serverless Operator.
Install the OpenShift CLI (oc).

Procedure

Create a file named serving.yaml and copy the following example YAML into it:

apiVersion: operator.knative.dev/v1beta1
kind: KnativeServing
metadata:
    name: knative-serving
    namespace: knative-serving

Apply the serving.yaml file:
```
$ oc apply -f serving.yaml
```

Verification

To verify the installation is complete, enter the following command:
```
$ oc get knativeserving.operator.knative.dev/knative-serving -n knative-serving --template='{{range .status.conditions}}{{printf "%s=%s\n" .type .status}}{{end}}'
```
Example output
```
DependenciesInstalled=True
DeploymentsAvailable=True
InstallSucceeded=True
Ready=True
```
It may take a few seconds for the Knative Serving resources to be created.

If the conditions have a status of Unknown or False, wait a few moments and then check again after you have confirmed that the resources have been created.

Check that the Knative Serving resources have been created:

$ oc get pods -n knative-serving

Example output

NAME                                                        READY   STATUS      RESTARTS   AGE
activator-67ddf8c9d7-p7rm5                                  2/2     Running     0          4m
activator-67ddf8c9d7-q84fz                                  2/2     Running     0          4m
autoscaler-5d87bc6dbf-6nqc6                                 2/2     Running     0          3m59s
autoscaler-5d87bc6dbf-h64rl                                 2/2     Running     0          3m59s
autoscaler-hpa-77f85f5cc4-lrts7                             2/2     Running     0          3m57s
autoscaler-hpa-77f85f5cc4-zx7hl                             2/2     Running     0          3m56s
controller-5cfc7cb8db-nlccl                                 2/2     Running     0          3m50s
controller-5cfc7cb8db-rmv7r                                 2/2     Running     0          3m18s
domain-mapping-86d84bb6b4-r746m                             2/2     Running     0          3m58s
domain-mapping-86d84bb6b4-v7nh8                             2/2     Running     0          3m58s
domainmapping-webhook-769d679d45-bkcnj                      2/2     Running     0          3m58s
domainmapping-webhook-769d679d45-fff68                      2/2     Running     0          3m58s
storage-version-migration-serving-serving-0.26.0--1-6qlkb   0/1     Completed   0          3m56s
webhook-5fb774f8d8-6bqrt                                    2/2     Running     0          3m57s
webhook-5fb774f8d8-b8lt5                                    2/2     Running     0          3m57s

Check that the necessary networking components have been installed to the automatically created knative-serving-ingress namespace:

$ oc get pods -n knative-serving-ingress

Example output

NAME                                      READY   STATUS    RESTARTS   AGE
net-kourier-controller-7d4b6c5d95-62mkf   1/1     Running   0          76s
net-kourier-controller-7d4b6c5d95-qmgm2   1/1     Running   0          76s
3scale-kourier-gateway-6688b49568-987qz   1/1     Running   0          75s
3scale-kourier-gateway-6688b49568-b5tnp   1/1     Running   0          75s

Next steps

If you want to use Knative event-driven architecture you can install Knative Eventing.