Knative on AWS: A Comprehensive Tutorial

Are you looking for a way to run your Kubernetes hosted functions as a service on AWS? Look no further than Knative! Knative is an open-source project that provides a set of building blocks for serverless applications on top of Kubernetes. In this tutorial, we will show you how to set up Knative on AWS and deploy your first serverless application.

Prerequisites

Before we get started, make sure you have the following:

• An AWS account
• A Kubernetes cluster running on AWS
• kubectl installed on your local machine
• The AWS CLI installed on your local machine

Step 1: Install Istio

Knative requires Istio to be installed on your Kubernetes cluster. Istio is an open-source service mesh that provides traffic management, security, and observability for microservices. To install Istio, follow the instructions in the Istio documentation.

Step 2: Install Knative

Once Istio is installed, you can install Knative. Knative consists of several components, including Serving, Eventing, and Build. In this tutorial, we will focus on Knative Serving, which provides a platform for deploying and serving serverless applications.

To install Knative Serving, run the following command:

kubectl apply -f https://github.com/knative/serving/releases/download/v0.25.0/serving-crds.yaml
kubectl apply -f https://github.com/knative/serving/releases/download/v0.25.0/serving-core.yaml

This will install the Knative Serving CRDs and core components.

Step 3: Configure Knative

Before you can deploy your serverless application, you need to configure Knative. Knative uses a concept called a "route" to map incoming requests to a specific service. To create a route, you need to create a Knative service.

To create a Knative service, create a YAML file with the following contents:

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: hello
spec:
  template:
    spec:
      containers:
        - image: gcr.io/knative-samples/helloworld-go
          env:
            - name: TARGET
              value: "Knative on AWS"

This YAML file defines a Knative service called "hello" that uses the "helloworld-go" image from the Knative samples repository. The "TARGET" environment variable is set to "Knative on AWS".

To create the Knative service, run the following command:

kubectl apply -f <filename>.yaml

Replace <filename> with the name of your YAML file.

Step 4: Expose the Service

Now that you have created a Knative service, you need to expose it to the internet. Knative uses Istio to manage traffic, so you need to create an Istio gateway and virtual service.

To create an Istio gateway, create a YAML file with the following contents:

apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: knative-ingress-gateway
spec:
  selector:
    istio: ingressgateway
  servers:
    - port:
        number: 80
        name: http
        protocol: HTTP
      hosts:
        - "*"

This YAML file defines an Istio gateway called "knative-ingress-gateway" that listens on port 80 and accepts all incoming requests.

To create the Istio gateway, run the following command:

kubectl apply -f <filename>.yaml

Replace <filename> with the name of your YAML file.

Next, create a virtual service that maps incoming requests to your Knative service. Create a YAML file with the following contents:

apiVersion: networking.istio.io/v1alpha3
kind: VirtualService
metadata:
  name: hello
spec:
  hosts:
    - "*"
  gateways:
    - knative-ingress-gateway
  http:
    - match:
        - uri:
            prefix: /
      route:
        - destination:
            host: istio-ingressgateway.istio-system.svc.cluster.local
            port:
              number: 80
            subset: hello
    - route:
        - destination:
            host: knative-ingressgateway.istio-system.svc.cluster.local
            port:
              number: 80
            subset: hello

This YAML file defines a virtual service called "hello" that maps incoming requests to your Knative service. The subset field specifies the version of your service to use. In this case, we only have one version, so we use the default value.

To create the virtual service, run the following command:

kubectl apply -f <filename>.yaml

Replace <filename> with the name of your YAML file.

Step 5: Test the Service

Now that you have exposed your Knative service to the internet, you can test it by sending an HTTP request to the Istio gateway. To get the URL of your service, run the following command:

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

This will output the URL of your service. Copy the URL and paste it into your web browser. You should see a message that says "Hello Knative on AWS!".

Congratulations, you have successfully deployed your first serverless application on Knative!

Conclusion

Knative provides a powerful platform for deploying and serving serverless applications on top of Kubernetes. By following this tutorial, you have learned how to set up Knative on AWS and deploy your first serverless application. We hope this tutorial has been helpful and we look forward to seeing what you build with Knative!

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