How to Create Ingress in Kubernetes: Simple Guide

To create an Ingress in Kubernetes, define an Ingress resource YAML that specifies rules to route external HTTP(S) traffic to internal services. Apply this YAML using kubectl apply -f after ensuring an ingress controller is installed in your cluster.

Syntax

An Ingress resource defines rules to route external traffic to Kubernetes services. Key parts include:

• apiVersion: The API group and version, usually networking.k8s.io/v1.
• kind: Always Ingress for ingress resources.
• metadata: Name and labels for the ingress.
• spec: Contains rules that map hostnames and paths to backend services.
• backend: Defines the service name and port to route traffic to.

yaml

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

Example

This example creates an ingress that routes all traffic from myapp.local to a service named myapp-service on port 80. It assumes you have an ingress controller installed like NGINX Ingress Controller.

yaml

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /
spec:
  rules:
  - host: myapp.local
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp-service
            port:
              number: 80

Output

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

Common Pitfalls

• Not installing an ingress controller before creating ingress resources will cause no traffic routing.
• Incorrect host or path values can prevent traffic from reaching services.
• Missing or wrong service name or port in backend causes routing failures.
• For local testing, forgetting to add the ingress host to your /etc/hosts file prevents DNS resolution.

yaml

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

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

Quick Reference

Remember these tips when creating ingress:

• Always install an ingress controller (e.g., NGINX, Traefik) before applying ingress resources.
• Use networking.k8s.io/v1 API version for Kubernetes 1.19+.
• Specify pathType as Prefix or Exact to control path matching.
• Use annotations to customize ingress controller behavior.
• Test DNS or hosts file to resolve ingress hostnames.

Key Takeaways

Install an ingress controller before creating ingress resources to enable traffic routing.

Define ingress rules with correct host, path, service name, and port for proper routing.

Use the latest API version networking.k8s.io/v1 and specify pathType for path matching.

Annotations help customize ingress behavior for specific controllers like NGINX.

For local testing, update your hosts file to resolve ingress hostnames.