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In this guide, you’ll learn how to deploy your application to a Kubernetes development environment using GitHub Actions. We’ll assume your Kubernetes manifests already contain the correct values, then show you how to add a dev-deploy job that replaces tokens, creates a MongoDB secret, and applies your manifests.

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1. Update the GitHub Actions Workflow

Open .github/workflows/main.yml and add the dev-deploy job: 
name: Solar System Workflow

on:
  workflow_dispatch:
  push:
    branches:
      - main
      - 'feature/*'

env:
  MONGO_URI: 'mongodb+srv://supercluster.d83jj.mongodb.net/superData'
  MONGO_USERNAME: ${{ vars.MONGO_USERNAME }}
  MONGO_PASSWORD: ${{ secrets.MONGO_PASSWORD }}

jobs:
  unit-testing:
    # …

  code-coverage:
    # …

  docker:
    # …

  dev-deploy:
    runs-on: ubuntu-latest
    needs: docker
    steps:
      - name: Checkout repository
        uses: actions/checkout@v3

      - name: Replace tokens in manifest files
        uses: cschleiden/replace-tokens@v1
        with:
          tokenPrefix: '_'
          tokenSuffix: '_'
          files: kubernetes/development/*.yaml
        env:
          NAMESPACE: ${{ vars.NAMESPACE }}
          REPLICAS: ${{ vars.REPLICAS }}
          IMAGE: ${{ vars.DOCKERHUB_USERNAME }}/solar-system:${{ github.sha }}
          INGRESS_IP: ${{ env.INGRESS_IP }}

      - name: Verify updated manifests
        run: |
          cat kubernetes/development/*.yaml

      - name: Create MongoDB Secret
        run: |
          kubectl -n ${{ vars.NAMESPACE }} create secret generic mongo-db-creds \
            --from-literal=MONGO_URI=${{ env.MONGO_URI }} \
            --from-literal=MONGO_USERNAME=${{ env.MONGO_USERNAME }} \
            --from-literal=MONGO_PASSWORD=${{ secrets.MONGO_PASSWORD }} \
            --save-config \
            --dry-run=client \
            -o yaml | kubectl apply -f -

      - name: Deploy to Dev Environment
        run: |
          kubectl apply -f kubernetes/development

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2. Kubernetes Deployment Manifest

Ensure your deployment.yaml in kubernetes/development/ references the secret for environment variables: 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: solar-system
  namespace: _NAMESPACE_
  labels:
    app: solar-system
spec:
  replicas: _REPLICAS_
  selector:
    matchLabels:
      app: solar-system
  template:
    metadata:
      labels:
        app: solar-system
    spec:
      containers:
      - name: solar-system
        image: _IMAGE_
        imagePullPolicy: Always
        ports:
        - containerPort: 3000
      envFrom:
      - secretRef:
          name: mongo-db-creds

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3. Repository Variables and Secrets

Configure the following under Settings > Secrets and variables in your GitHub repository.
The image shows a GitHub repository settings page focused on "Secrets and variables" under "Actions." It displays options for managing environment and repository variables, with some variables listed.
Variable / SecretTypeDescription
MONGO_URIEnvironment VariableMongoDB connection string.
MONGO_USERNAMERepository VariableUsername for MongoDB.
MONGO_PASSWORDEncrypted SecretPassword for MongoDB.
NAMESPACERepository VariableKubernetes namespace (e.g., development).
REPLICASRepository VariableNumber of pod replicas (e.g., 2).
DOCKERHUB_USERNAMERepository VariableDocker Hub account name.

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4. Running the Workflow

Push your changes to main or any feature/* branch. Then, monitor the pipeline in the Actions tab of your repository.
The image shows a GitHub Actions page for a repository named "solar-system," displaying a list of workflow runs with their statuses and details.
The dev-deploy job runs after the docker job (and its dependencies: unit-testing and code-coverage). It checks out the repo, replaces tokens, creates the MongoDB secret, and applies the Kubernetes manifests.
The image shows a GitHub Actions workflow in progress, displaying a series of jobs including unit testing, code coverage, containerization, and deployment. The workflow is visualized with a flowchart indicating the status of each step.

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5. Verifying in Kubernetes

Once the workflow succeeds, confirm the resources: 
kubectl -n development get secrets
kubectl -n development get all
You should see:
  • mongo-db-creds secret
  • Deployment and Pods for solar-system
  • Service and Ingress resources

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6. Accessing the Application

Retrieve and open the ingress endpoint: 
kubectl -n development get ingress
Open the HOSTNAME in your browser.
If you encounter a self-signed certificate warning, safely accept it to proceed to the application.
This lesson covers creating a Kubernetes secret and deploying to a development cluster via GitHub Actions. Integration testing for this deployment will be addressed in an upcoming article.
  • [GitHub Actions Documentation][GitHub Actions]
  • [GitHub Secrets and Variables][GitHub Secrets and Variables docs]
  • [Kubernetes Secrets][Kubernetes Secrets]
  • [Kubernetes Ingress][Ingress docs]

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