#100DaysOfSRE (Day 32): Advanced Kubernetes: Ingress, ConfigMaps, Secrets & Helm

In Day 31, we deployed a Python-based backend, frontend, and PostgreSQL database on Minikube using Kubernetes manifests. Now, let’s enhance our setup by adding:

✅ Ingress Controller for external access
✅ ConfigMaps & Secrets for secure configuration
✅ Helm Charts for easier deployment management

---

Step 1: Add an Ingress Controller for External Access

By default, Kubernetes services are only accessible inside the cluster. Instead of using NodePort, we will configure an Ingress Controller to route requests.

Install Ingress Controller on Minikube

minikube addons enable ingress

Define an Ingress Resource

ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  namespace: myapp
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: myapp.local
    http:
      paths:
      - path: /backend
        pathType: Prefix
        backend:
          service:
            name: backend
            port:
              number: 5000
      - path: /
        pathType: Prefix
        backend:
          service:
            name: frontend
            port:
              number: 3000

Apply the Ingress Configuration

kubectl apply -f ingress.yaml

Test the Ingress

Update /etc/hosts (Linux/macOS) to map myapp.local to Minikube’s IP:

echo  "$(minikube ip) myapp.local" | sudo tee -a /etc/hosts

Now, visit http://myapp.local/ for the frontend and http://myapp.local/backend for the backend!

---

Step 2: Use ConfigMaps & Secrets for Secure Configuration

Instead of hardcoding environment variables, we will use ConfigMaps and Secrets.

Create a ConfigMap for Database URL

configmap.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-config
  namespace: myapp
data:
  DATABASE_URL: "postgresql://user:password@postgres:5432/mydatabase"

Create a Secret for Database Credentials

secret.yaml

apiVersion: v1
kind: Secret
metadata:
  name: db-secret
  namespace: myapp
type: Opaque
data:
  POSTGRES_USER: dXNlcg==  # Base64 encoded 'user'
  POSTGRES_PASSWORD: cGFzc3dvcmQ=  # Base64 encoded 'password'

Modify Backend Deployment to Use ConfigMap & Secret

backend-deployment.yaml

apiVersion: apps/v1
kind: Deployment
metadata:
  name: backend
  namespace: myapp
spec:
  replicas: 1
  selector:
    matchLabels:
      app: backend
  template:
    metadata:
      labels:
        app: backend
    spec:
      containers:
      - name: backend
        image: python:3.10
        env:
        - name: DATABASE_URL
          valueFrom:
            configMapKeyRef:
              name: app-config
              key: DATABASE_URL
        - name: POSTGRES_USER
          valueFrom:
            secretKeyRef:
              name: db-secret
              key: POSTGRES_USER
        - name: POSTGRES_PASSWORD
          valueFrom:
            secretKeyRef:
              name: db-secret
              key: POSTGRES_PASSWORD
        ports:
        - containerPort: 5000

Apply ConfigMaps & Secrets

kubectl apply -f configmap.yaml
kubectl apply -f secret.yaml
kubectl apply -f backend-deployment.yaml

---

Step 3: Use Helm Charts for Deployment Management

Manually managing Kubernetes YAML files is tedious. Instead, we can use Helm, the package manager for Kubernetes.

Install Helm

brew install helm # macOS 
choco install kubernetes-helm # Windows

Create a Helm Chart

helm create myapp-chart

Modify Helm Chart to Deploy the App

Inside myapp-chart/values.yaml, update the service and deployment values.

myapp-chart/values.yaml

backend:
  image: python:3.10
  service:
    type: ClusterIP
    port: 5000

frontend:
  image: node:18
  service:
    type: ClusterIP
    port: 3000

database:
  image: postgres:15
  service:
    type: ClusterIP
    port: 5432
  env:
    POSTGRES_USER: user
    POSTGRES_PASSWORD: password
    POSTGRES_DB: mydatabase

Deploy the Application using Helm

helm install myapp ./myapp-chart

Check the Helm Deployment

helm list
kubectl get pods -n myapp

Upgrade the Helm Release

If you modify the configuration:

helm upgrade myapp ./myapp-chart

Uninstall the Helm Release

helm uninstall myapp

---

Final Thoughts

Key Takeaways
✅ Ingress Controllers expose applications externally with routing rules
✅ ConfigMaps & Secrets store environment variables securely
✅ Helm simplifies Kubernetes deployments with reusable charts

What’s Next?
🔹 Day 33: Monitoring Kubernetes Apps with Prometheus & Grafana
🔹 Day 34: CI/CD Pipelines for Kubernetes Deployments

Stay tuned for more Kubernetes posts in the #100DaysOfSRE series!