Knative

In this exercise, you will install Knative to enable serverless workloads on your Kubernetes cluster. Knative manages the deployment, scaling, and routing of stateless applications, and integrates with ingress controllers like Kourier or Istio to expose services externally. This allows Knative services to scale to zero when idle and become accessible from outside the cluster without relying on external cloud-native serverless platforms—making it ideal for on-premises or hybrid cloud environments.

Important

This tutorial describes the steps using the Rafay Web Console. The entire workflow can also be fully automated and embedded into an automation pipeline

Assumptions¶

You have already provisioned or imported a Kubernetes cluster into your Rafay Org with a load balancer.

Step 1: Create Knative Operator Namespace¶

Login into the Web Console
Navigate to Infrastructure -> Namespaces
Create a new namespace, enter the name knative-operator and select type as Wizard
In the placement section, select a cluster
Click Save & Go to Publish
Publish the namespace

Step 1: Create Knative Operator repository¶

Navigate to Integrations -> Repositories
Click New Repository
Enter the name knative-operator and select type as Helm
Click Create

Enter https://knative.github.io/operator for the endpoint
Click Save

Click the "validate" button on the repo

Step 3: Create Knative Operator Add-on¶

Navigate to Infrastructure -> Add-Ons
Select New Add-On -> Create New Add-On
Enter knative-operator for the name
Set the type as Helm 3
Select Pull files from repository
Select Helm for the repository type
Select the namespace knative-operator

Select New Version
Enter a version name
Enter knative-operator for the chart name
Enter v1.18.1 for teh chart version
Click Save Changes

Step 4: Create Knative Serving Namespace¶

Navigate to Infrastructure -> Namespaces
Create a new namespace, enter the name knative-serving and select type as Wizard
In the placement section, select a cluster
Click Save & Go to Publish
Publish the namespace

Step 5: Create Knative Serving Add-on¶

Navigate to Infrastructure -> Add-Ons
Select New Add-On -> Create New Add-On
Enter knative-serving for the name
Set the type as K8s YAML
Select Upload files manually
Select the namespace knative-serving
Click Create

Select New Version
Enter a version name
Save the following yaml to a file. Update the domain section with your domain.

apiVersion: operator.knative.dev/v1beta1
kind: KnativeServing
metadata:
  name: knative-serving
  namespace: knative-serving
spec:
  # ...
  ingress:
    kourier:
      enabled: true
  config:
    network:
      ingress-class: "kourier.ingress.networking.knative.dev"
    domain:
      example.com: ""

Click Upload and select the previously created file
Click Save Changes

Step 6: Create Knative Eventing Namespace¶

Navigate to Infrastructure -> Namespaces
Create a new namespace, enter the name knative-eventing and select type as Wizard
In the placement section, select a cluster
Click Save & Go to Publish
Publish the namespace

Step 7: Create Knative Eventing Add-on¶

Navigate to Infrastructure -> Add-Ons
Select New Add-On -> Create New Add-On
Enter knative-eventing for the name
Set the type as K8s YAML
Select Upload files manually
Select the namespace knative-eventing
Click Create

Select New Version
Enter a version name
Save the following yaml to a file. Update the domain section with your domain.

apiVersion: v1
kind: Namespace
metadata:
  name: knative-eventing
---
apiVersion: operator.knative.dev/v1beta1
kind: KnativeEventing
metadata:
  name: knative-eventing
  namespace: knative-eventing

Click Upload and select the previously created file
Click Save Changes

Step 8: Create Blueprint¶

Navigate to Infrastructure -> Blueprints
Click New Blueprint
Enter a name for the blueprint
Click Save
Enter a version name
Click Configure Add-Ons
Select the previously created Knative add-ons
Select the knative-operator add-on as the dependency for the serving and eventing add-ons
Click Save Changes

Click Save Changes

Click Save Changes

Step 8: Apply Blueprint¶

Navigate to Infrastructure -> Clusters
Click the gear icon on your cluster and select Update Blueprint
Select the previously created blueprint
Click Save and Publish

After a few seconds, the blueprint with the Knative add-ons will be published on the cluster.

Step 9: Test Knative¶

In this step, you will create a sample Knative service that deploys a serverless HTTP service that responds like httpbin.org, managed and autoscaled by Knative.

Create a file named app.yaml with the following contents

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: helloworld
  namespace: default
spec:
  template:
    spec:
      containers:
        - image: docker.io/kennethreitz/httpbin
          ports:
            - containerPort: 80

Type the following command to create the resource

kubectl apply -f app.yaml

Run the following command to watch for Knative autoscaling

watch kubectl get pods -n default

Run the following command from your local machine to create a port-forward connection to the Knative Kourier service

kubectl port-forward -n knative-serving svc/kourier 8080:80

Run the following command to get the hostname of the application

kubectl get ksvc helloworld -o jsonpath='{.status.url}'

You will see output similar to the following:

http://helloworld.default.example.com

Run the following command to access to application. Be sure to update the hostname with the hostname from the previous command.

curl -H "Host: helloworld.default.example.com" http://localhost:8080

You will see the output of the running "watch" command from above show the scaled application when the curl request was made. This will automatically scale down after 90 seconds.