Host-based routing in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Host-based Routing in Kubernetes Ingress

What is the primary purpose of host-based routing in a Kubernetes Ingress resource?

A To route traffic to different backend services based on the requested hostname

B To route traffic based on the client IP address

C To route traffic to services based on the container port number

D To route traffic only to services running on the same node as the Ingress controller

💡 Hint

Think about how Ingress directs requests to different services depending on the URL host.

Host-based routing allows the Ingress controller to send requests to different backend services depending on the hostname in the HTTP request. This enables multiple domains to be served from the same Ingress.

❓ Configuration

intermediate

Identify the Correct Host-based Routing Ingress YAML Snippet

Which Ingress YAML snippet correctly routes traffic to service-a when the host is app.example.com?

A

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: service-a
            port:
              number: 80

B

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /app
        pathType: Prefix
        backend:
          service:
            name: service-b
            port:
              number: 80

C

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: service-a
            port:
              number: 80

D

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
spec:
  rules:
  - host: app.example.com
    http:
      paths:
      - path: /
        pathType: Exact
        backend:
          service:
            name: service-a
            port:
              number: 8080

💡 Hint

Check the host, path, and port values carefully.

Option C correctly sets the host to app.example.com, the path to / with prefix matching, and routes to service-a on port 80.

💻 Command Output

advanced

Output of kubectl get ingress with Multiple Hosts

Given an Ingress resource with two host rules: app1.example.com routing to service1 and app2.example.com routing to service2, what is the output of kubectl get ingress my-ingress?

Kubernetes

kubectl get ingress my-ingress

A Error from server (NotFound): ingresses.networking.k8s.io "my-ingress" not found

B

NAME         CLASS    HOSTS                       ADDRESS        PORTS   AGE
my-ingress   <none>   app1.example.com              192.168.1.10   80      10m

C

NAME         CLASS    HOSTS                       ADDRESS        PORTS   AGE
my-ingress   <none>   app2.example.com              192.168.1.10   80      10m

D

NAME         CLASS    HOSTS                       ADDRESS        PORTS   AGE
my-ingress   <none>   app1.example.com,app2.example.com   192.168.1.10   80      10m

💡 Hint

Remember that multiple hosts appear comma-separated in the HOSTS column.

The kubectl get ingress command lists all hosts configured in the Ingress resource separated by commas in the HOSTS column.

❓ Troubleshoot

advanced

Troubleshooting Host-based Routing Failure

You have an Ingress configured with host app.example.com routing to service-a. Requests to app.example.com return 404 errors. Which is the most likely cause?

A The service <code>service-a</code> is exposing the wrong port number

B The Ingress controller is not running or not configured properly

C The DNS for <code>app.example.com</code> is not pointing to the Ingress controller's IP

D The pod labels do not match the service selector

💡 Hint

Consider what happens if the Ingress controller is missing or misconfigured.

If the Ingress controller is not running or misconfigured, it cannot route requests, causing 404 errors even if the Ingress resource is correct.

🔀 Workflow

expert

Correct Order to Deploy Host-based Routing Ingress

Arrange the steps in the correct order to deploy host-based routing using Kubernetes Ingress.

A 1,2,3,4

B 3,2,1,4

C 1,3,2,4

D 2,1,3,4

💡 Hint

Think about what must exist before the Ingress can route traffic.

You must first create backend services and deployments, then deploy the Ingress controller, then create the Ingress resource, and finally verify DNS settings.