k8s/StudyNotes/k8s Ingress Service

Service [ clusterPort, nodePort]
- Problem service nodePort > 30k, so need proxy server for port 80, 443 to this port.
On cloud set to LoadBalancer, still nodePort + talks to cloud paltform to configure the LB
- e.g. svc1 p38080, svc2 p38282, need yet another load-balancer

Ingress - l7 loadbalancer config, path based.

Ingress controller Nginx, HAPROXY, traefik, GCE(Google), Istio
- Not deployed by default
  - e.g. Deploy nginx-ingress-controller as Deployment + ConfigMap + Service + ServiceAccount

Ingress Resource

apiVersion: networking.k8s.io/v1
kind: Ingress
spec: 
  rules:
  - host: wear.my-online-store.com 
    http:
      paths:
      - path: /wear
        pathType: Prefix
        backend:
          serviceName: wear-service
          servicePort: 80
      - path: /watch
        pathType: Prefix
        backend:
          serviceName: watch-service
          servicePort: 80

From 1.20, kubectl create ingress <ingress-name> --rule="host.com/path*=wear-svc:80"

Different ingress controllers can have annotations to set feature.

e.g. for nginx to strip /path/ when sending to backend service

  annotations:
    nginx.ingress.kubernetes.io/rewrite-target: /

annotations:
  nginx.ingress.kubernetes.io/rewrite-target: /$2
...
spec:
  rules:
  - http:
     paths:
     - path: /something(/|$)(.*)