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In this guide, we’ll walk through our CI/CD pipeline stages and demonstrate how to deploy a Dockerized application to Kubernetes clusters. You’ll learn how to:
  • Build and test your code
  • Containerize with Docker
  • Deploy to a development cluster
  • Run integration tests
  • Promote to production after manual approval

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Deployment Pipeline Overview

We’ve already completed:
StagePurpose
Unit TestingValidate code logic with npm test
Code CoverageMeasure test coverage using npm run coverage
Docker ContainerizationPackage the app into a Docker image
Next, the pipeline will:
  1. Push the Docker image to a container registry
  2. Deploy to a Kubernetes development environment
  3. Execute integration tests against the dev cluster
  4. Await manual approval
  5. Promote the same deployment to the production environment

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Local Development Commands

Before diving into Kubernetes, run these commands locally to verify your application:
StepCommandDescription
Installnpm installInstall project dependencies
Testnpm testExecute unit tests
Coveragenpm run coverageGenerate code coverage report
Build Imagedocker build -t my-app:latest .Create a Docker image
Run Imagedocker run -p 3000:3000 my-app:latestLaunch the container on port 3000
Push Imagedocker push my-app:latestUpload the image to your registry
# Example: Build and run locally
npm install
npm test
npm run coverage
docker build -t my-app:latest .
docker run -p 3000:3000 my-app:latest
docker push my-app:latest

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Deploying to Kubernetes

To deploy the Docker image, prepare these Kubernetes manifests:
  • Deployment: Defines Pods and ReplicaSets in k8s/deployment.yaml
  • Service: Exposes Pods internally via k8s/service.yaml
  • Ingress: Routes external HTTP traffic using k8s/ingress.yaml
Apply them in sequence: 
kubectl apply -f k8s/deployment.yaml
kubectl apply -f k8s/service.yaml
kubectl apply -f k8s/ingress.yaml

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Integration Testing on Dev

Once the resources are live, validate the deployment: 
curl http://dev.my-app.example.com/health
A 200 OK response confirms that the application is operating correctly in the development cluster.
Ensure your Kubernetes context is set to the development cluster:
kubectl config use-context dev-cluster

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Manual Approval Gate

Before proceeding to production, implement a manual approval step in your CI/CD workflow. This prevents unintentional releases.
An administrator must review the integration test results and approve the release.
Skipping this step can lead to unverified changes reaching production.

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Production Deployment

After approval, deploy to the production cluster using the same manifests:
  1. Switch to the production context: 
    kubectl config use-context prod-cluster
  2. Apply the manifests: 
    kubectl apply -f k8s/deployment.yaml
kubectl apply -f k8s/service.yaml
kubectl apply -f k8s/ingress.yaml
  3. Run production integration tests: 
    curl http://my-app.example.com/health
Optionally, configure post-deployment alerts or monitoring checks to ensure reliability.

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Next Steps

In the next lesson, we’ll cover Kubernetes fundamentals in depth and build automated workflow files for our CI/CD pipeline.

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