Ingress: HTTP routing into the cluster

Key points

• An Ingress is a set of HTTP rules mapping host and path to a Service. One cloud load balancer serves everything behind it.
• The Ingress object does nothing on its own. You must install a controller such as ingress-nginx, Traefik or the cloud's own.
• Choose the controller with ingressClassName, and set pathType to Prefix or Exact on every path.
• TLS terminates here. Point tls.secretName at a Secret, or let cert-manager issue and renew it automatically.
• Gateway API is the official successor and is GA. Before piling on more nginx annotations, check whether it fits.

Example

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: shop
spec:
  ingressClassName: nginx
  tls:
    - hosts:
        - shop.example.com
      secretName: shop-tls
  rules:
    - host: shop.example.com
      http:
        paths:
          - path: /api
            pathType: Prefix
            backend:
              service:
                name: orders
                port:
                  number: 80
          - path: /
            pathType: Prefix
            backend:
              service:
                name: web
                port:
                  number: 80

One Ingress, one load balancer, many services. Gateway API is where this is heading.