Ingress controllers (Nginx, Traefik) in Kubernetes - Commands & Configuration

Introduction

When you run multiple apps inside Kubernetes, you need a way to let users reach them from outside. Ingress controllers like Nginx and Traefik help by managing how external traffic gets routed to your apps safely and easily.

When you want to expose several web apps on the same IP but different URLs or paths.

When you need to manage SSL certificates for your apps automatically.

When you want to control traffic rules like redirects or load balancing inside your cluster.

When you want to monitor and log incoming requests centrally.

When you want to simplify external access without creating many LoadBalancer services.

Config File - ingress.yaml

ingress.yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: example-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /$2
spec:
  ingressClassName: nginx
  rules:
  - host: example.local
    http:
      paths:
      - path: /app1(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: app1-service
            port:
              number: 80
      - path: /app2(/|$)(.*)
        pathType: Prefix
        backend:
          service:
            name: app2-service
            port:
              number: 80

This file defines an Ingress resource that routes traffic based on URL paths to two different services inside the cluster.

metadata.annotations tells Nginx to rewrite the URL path before sending it to the service.

spec.ingressClassName specifies that this Ingress uses the Nginx controller.

spec.rules define the host and paths to route traffic to the right backend services.

Commands

This command creates the Ingress resource in Kubernetes, telling the Ingress controller how to route external traffic to your services.

Terminal

kubectl apply -f ingress.yaml

Expected Output

ingress.networking.k8s.io/example-ingress created

This command checks the status and details of the Ingress resource to confirm it was created and see its rules.

Terminal

kubectl get ingress example-ingress

Expected Output

NAME              CLASS    HOSTS          ADDRESS        PORTS   AGE

example-ingress   nginx    example.local  192.168.99.100 80      10s

This command shows detailed information about the Ingress, including backend services and any events or errors.

Terminal

kubectl describe ingress example-ingress

Expected Output

Name:             example-ingress

Namespace:        default

Address:          192.168.99.100

Default backend:  <none>

Rules:

  Host           Path  Backends

  ----           ----  --------

  example.local

                 /app1(/|$)(.*)   app1-service:80 (10.1.1.10:80)

                 /app2(/|$)(.*)   app2-service:80 (10.1.1.11:80)

Annotations:     nginx.ingress.kubernetes.io/rewrite-target: /$2

Events:

  Type    Reason  Age   From                      Message

  ----    ------  ----  ----                      -------

  Normal  Sync    10s   nginx-ingress-controller  Scheduled for sync

This command verifies that the Nginx Ingress controller pods are running in the cluster namespace where it is installed.

Terminal

kubectl get pods -n ingress-nginx

Expected Output

NAME                                        READY   STATUS    RESTARTS   AGE

nginx-ingress-controller-5d7f9f7d7f-abc12  1/1     Running   0          5m

Key Concept

If you remember nothing else from this pattern, remember: Ingress controllers route external traffic to your Kubernetes services based on rules you define.

Common Mistakes

Not specifying the correct ingressClassName matching the installed controller

The Ingress resource won't be picked up by any controller, so traffic won't route correctly.

Check which ingress controller is installed and use its class name exactly in the Ingress spec.

Forgetting to create or install the Ingress controller before applying Ingress resources

Ingress resources depend on the controller to function; without it, rules have no effect.

Install the Nginx or Traefik Ingress controller first using their official manifests or Helm charts.

Using incorrect path syntax or missing rewrite annotations

Requests may not reach the backend services correctly or cause 404 errors.

Use proper pathType and rewrite-target annotations as per the controller's documentation.

Summary

Create an Ingress resource to define routing rules for external traffic to services.

Use kubectl apply to deploy the Ingress and kubectl get/describe to verify it.

Ensure the Ingress controller (Nginx or Traefik) is installed and running to handle the traffic.