How to Access a Knative Service?

I was getting confused and frustrated working with different platforms for running Knative experiments, specifically, what should be the IP_ADDRESS in this curl command? 🤔

curl -H "Host: helloworld-nodejs.default.example.com" http://{IP_ADDRESS}
Hello Node.js Sample v1!

I generally switch among the following platforms on my Mac to experiment Knative Serving samples/features/use cases:

1. Minikube
2. Docker for Desktop
3. IBM Cloud

Here is my cheat sheet on how to access a sample Knative service on all three platforms:

Minikube

Step 1: Determine which Gateway are you using. This mostly sets the gateway to istio-ingressgateway since Knative 0.3.x and onwards use istio-ingressgateway.

INGRESSGATEWAY=knative-ingressgateway
if kubectl get configmap config-istio -n knative-serving &> /dev/null; then
    INGRESSGATEWAY=istio-ingressgateway
fi

Step 2: Find the IP address of your cluster with the Port

echo $(minikube ip):$(kubectl get svc $INGRESSGATEWAY --namespace istio-system --output 'jsonpath={.spec.ports[?(@.port==80)].nodePort}')
192.168.64.19:31282

Step 3: Access the Knative Service

curl -H "Host: helloworld-nodejs.default.example.com" http://192.168.64.19:31282
Hello Node.js Sample v1!

Docker For Desktop

Step 1: Determine which Gateway are you using

INGRESSGATEWAY=knative-ingressgateway
if kubectl get configmap config-istio -n knative-serving &> /dev/null; then
    INGRESSGATEWAY=istio-ingressgateway
fi

Step 2: Find the NodePort of the ingress gateway for port 80

echo $(kubectl get svc $INGRESSGATEWAY --namespace istio-system --output 'jsonpath={.spec.ports[?(@.port==80)].nodePort}')
31082

Step 3: Access the Knative Service

curl -H "Host: helloworld-nodejs.default.example.com" http://127.0.0.1:31082
Hello Node.js Sample v1!

IBM Cloud

Step 1. Determine the Host

kubectl get ksvc helloworld-nodejs
NAME                            DOMAIN                                                                                  LATESTCREATED                         LATESTREADY                           READY   REASON
helloworld-nodejs   helloworld-nodejs.default.<cluster-name>.<region>.containers.appdomain.cloud   helloworld-nodejs-f2w4p   helloworld-nodejs-f2w4p   True

Step 2. Access the Knative Service

curl helloworld-nodejs.default.<cluster-name>.<region>.containers.appdomain.cloud
Hello Node.js Sample v1!

Hopefully this cheat sheet is helpful and minimizes any confusion with your cluster IP and Port. 👍