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Lab 8.4 - Multi-domains and Virtual Hosts

Lab Objectives​

By the end of this lab, you will be able to:

  • Configure multiple domains in a single Ingress.
  • Route traffic to different applications based on the domain.
  • Understand virtual hosts.
  • Configure TLS for multiple domains.
  • Test access to multiple domains.

Estimated Duration​

45-60 minutes

Prerequisites​

  • kubectl installed and configured.
  • Kubernetes cluster with Ingress Controller.
  • Knowledge of Ingress (previous labs).

Part 1: Deploying Multiple Applications​

Let's deploy three different applications for three domains.

Step 1.1: Application for Domain1​

Create app1-deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app1
spec:
  replicas: 2
  selector:
    matchLabels:
      app: app1
  template:
    metadata:
      labels:
        app: app1
    spec:
      containers:
      - name: nginx
        image: nginx:1.20
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: app1-service
spec:
  selector:
    app: app1
  ports:
  - port: 80
    targetPort: 80

Step 1.2: Application for Domain2​

Create app2-deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app2
spec:
  replicas: 2
  selector:
    matchLabels:
      app: app2
  template:
    metadata:
      labels:
        app: app2
    spec:
      containers:
      - name: httpd
        image: httpd:2.4
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: app2-service
spec:
  selector:
    app: app2
  ports:
  - port: 80
    targetPort: 80

Step 1.3: Application for Domain3​

Create app3-deployment.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: app3
spec:
  replicas: 2
  selector:
    matchLabels:
      app: app3
  template:
    metadata:
      labels:
        app: app3
    spec:
      containers:
      - name: nginx
        image: nginx:1.20
        ports:
        - containerPort: 80
---
apiVersion: v1
kind: Service
metadata:
  name: app3-service
spec:
  selector:
    app: app3
  ports:
  - port: 80
    targetPort: 80

Apply all deployments:

kubectl apply -f app1-deployment.yaml
kubectl apply -f app2-deployment.yaml
kubectl apply -f app3-deployment.yaml

Part 2: Multi-domain Ingress Configuration​

Step 2.1: Create the Ingress with Multiple Domains​

Create ingress-multi-domain.yaml:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: multi-domain-ingress
spec:
  ingressClassName: nginx
  rules:
  # First domain
  - host: app1.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app1-service
            port:
              number: 80
  # Second domain
  - host: app2.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app2-service
            port:
              number: 80
  # Third domain
  - host: app3.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app3-service
            port:
              number: 80

Apply the Ingress:

kubectl apply -f ingress-multi-domain.yaml

Part 3: Configuring Hostnames​

Step 3.1: Add Entries to /etc/hosts​

Add the three domains to your /etc/hosts file (or Windows equivalent):

<INGRESS_IP> app1.local
<INGRESS_IP> app2.local
<INGRESS_IP> app3.local

Replace <INGRESS_IP> with your Ingress Controller IP.

Part 4: Testing the Domains​

Step 4.1: Test Each Domain​

Test access to each domain:

# Test app1.local
curl http://app1.local

# Test app2.local
curl http://app2.local

# Test app3.local
curl http://app3.local

You should see different responses depending on the domain.

Step 4.2: Verify with the Host Header​

You can also test with the Host header:

curl -H "Host: app1.local" http://<INGRESS_IP>
curl -H "Host: app2.local" http://<INGRESS_IP>
curl -H "Host: app3.local" http://<INGRESS_IP>

Part 5: TLS for Multiple Domains​

Step 5.1: Create Certificates for Each Domain​

If you are using cert-manager, create certificates for each domain:

apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: app1-tls-cert
spec:
  secretName: app1-tls-secret
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
  dnsNames:
  - app1.local
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: app2-tls-cert
spec:
  secretName: app2-tls-secret
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
  dnsNames:
  - app2.local
---
apiVersion: cert-manager.io/v1
kind: Certificate
metadata:
  name: app3-tls-cert
spec:
  secretName: app3-tls-secret
  issuerRef:
    name: selfsigned-issuer
    kind: ClusterIssuer
  dnsNames:
  - app3.local

Step 5.2: Configure TLS in the Ingress​

Modify the Ingress to include TLS:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: multi-domain-ingress-tls
spec:
  ingressClassName: nginx
  tls:
  - hosts:
    - app1.local
    secretName: app1-tls-secret
  - hosts:
    - app2.local
    secretName: app2-tls-secret
  - hosts:
    - app3.local
    secretName: app3-tls-secret
  rules:
  - host: app1.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app1-service
            port:
              number: 80
  - host: app2.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app2-service
            port:
              number: 80
  - host: app3.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: app3-service
            port:
              number: 80

Part 6: Cleanup​

Delete the resources:

kubectl delete ingress multi-domain-ingress
kubectl delete -f app1-deployment.yaml
kubectl delete -f app2-deployment.yaml
kubectl delete -f app3-deployment.yaml

Lab Summary​

In this lab, you configured an Ingress with multiple domains (virtual hosts). You learned how to route traffic to different applications based on the domain, configure TLS for multiple domains, and test access to each domain.

Next Steps​

This module on Ingress and Load Balancing is now complete. You can proceed to Module 9 on Security and RBAC.

Module 9: Security and RBAC

Lab created: December 2024