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Running a Serverless Node.js Application on Kubernetes with Knative

What Will You Learn in This Guide?​

In this guide, you will learn how to set up serverless architecture on Kubernetes.
With Knative Serving, you will run the Node.js application as an auto-scaling service.

🧠 Technical Summary​

Subject: Serverless services with Knative on Kubernetes
Problem: Operational burden of pod and scale management
Solution: Automatic scaling and scale-to-zero with Knative Serving
Steps: Knative installation → Network configuration → Service deployment → Testing

Preliminary Preparations​

The following should be ready before continuing:

  • A Kubernetes cluster with at least 2 CPUs and 4 GB RAM
  • kubectl command line tool
  • A Node.js image published on Docker Hub
  • Access to the cluster via kubectl

1. Knative Serving Setup​

Knative Serving runs serverless workloads on Kubernetes.

kubectl apply -f https://github.com/knative/serving/releases/download/knative-v1.8.0/serving-crds.yaml
kubectl apply -f https://github.com/knative/serving/releases/download/knative-v1.8.0/serving-core.yaml
  • These commands install Knative Serving components on the cluster.

Verify installation:


kubectl get pods -n knative-serving
  • All pods must be in Running state.

2. Network Layer (Courier) Configuration​

  1. Knative uses an ingress layer to route incoming traffic.
  • Kourier is preferred in this guide.

kubectl apply -f https://github.com/knative/net-kourier/releases/download/knative-v1.8.0/kourier.yaml

Set Knative to use Kourier:


kubectl patch configmap/config-network \
  -n knative-serving \
  --type merge \
  --patch '{"data":{"ingress-class":"kourier.ingress.networking.knative.dev"}}'

Get external IP address:


kubectl get svc kourier -n kourier-system

3. Domain Setting with Magic DNS (sslip.io)​

  1. Knative's Magic DNS feature is used for testing without a real domain name.

kubectl apply -f https://github.com/knative/serving/releases/download/knative-v1.8.0/serving-default-domain.yaml
  • This configuration automatically generates service URLs.

4. Deploying a Serverless Node.js Service (YAML)​

  1. First create a namespace for isolation:

kubectl create namespace serverless-app

Then create the service.yaml file:


apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: genixnode-node-demo
  namespace: serverless-app
spec:
  template:
    spec:
      containers:
        - image: knative-samples/helloworld-go
          ports:
            - containerPort: 8080
          env:
            - name: TARGET
              value: "GenixNode Dunyasi"
  • This YAML file defines the Knative Service.

Deploy the service:


kubectl apply -f service.yaml

5. Application Access and Testing​

  1. Get the service URL:

kubectl get ksvc -n serverless-app

Test in browser or with curl:


curl http://genixnode-node-demo.serverless-app.IP_ADRESI.sslip.io

🔁 Automatic Scaling (Scale-to-Zero) Test​

  1. Knative reduces the number of pods to 0 when there is no traffic.
  • If you do not send a request for a few minutes, the pods will be closed.

kubectl get pods -n serverless-app
  • Pods are started automatically when a new request arrives.

❓ Frequently Asked Questions (FAQ)​

1. Why is Knative preferred over Kubernetes? Provides automatic scaling and version management.

2. What does scale-to-zero bring? It reduces resource consumption and cost.

3. Can I use ingress instead of Kourier? Yes, Istio or Contour is supported.

4. Is it possible to use a real domain? Yes, a DNS record can be added.

Result​

In this guide, you set up a serverless Node.js service with Knative on Kubernetes. Now you can focus on application development instead of infrastructure management.

You can try this architecture immediately on the GenixNode Kubernetes infrastructure.