What is Kubernetes IngressClass?

Question

Accepted Answer

**IngressClass** — specify which Ingress controller handles an Ingress.

```yaml
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: nginx
  annotations:
    ingressclass.kubernetes.io/is-default-class: "true"
spec:
  controller: k8s.io/ingress-nginx
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: traefik
spec:
  controller: traefik.io/ingress-controller
---
apiVersion: networking.k8s.io/v1
kind: IngressClass
metadata:
  name: alb
spec:
  controller: ingress.k8s.aws/alb
---
# Ingress using specific class
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: myapp-ingress
spec:
  ingressClassName: nginx
  rules:
  - host: myapp.example.com
    http:
      paths:
      - path: /
        pathType: Prefix
        backend:
          service:
            name: myapp
            port:
              number: 80
```

```bash
# Commands
kubectl get ingressclass
kubectl describe ingressclass nginx

# Check default class
kubectl get ingressclass -o jsonpath='{range .items[*]}{.metadata.name}{"	"}{.metadata.annotations}{"
"}{end}'

# Check which controller is running
kubectl get pods -n ingress-nginx
kubectl get pods -n traefik

# Verify Ingress class
kubectl get ingress myapp-ingress -o jsonpath='{.spec.ingressClassName}'
```

**Controllers:**
- nginx: k8s.io/ingress-nginx.
- traefik: traefik.io/ingress-controller.
- ALB: ingress.k8s.aws/alb.
- gce: k8s.io/gce-ingress-controller.

DevOps: What is Kubernetes IngressClass?