Overview: VirtualServer and VirtualServer Routing in nginx-ingress

VirtualServer is a type of native custom ingress resource, which can act along the ingress resource or act as a replacement for the ingress resource that does load balancing. It provides extended flexibility and customizability for adding header annotations for handling routing and can act as a proxy loadbalancer within the server itself.

VirtualServer Routing:

VirtualServer Route defines route for VirtualServers. A VirtualServer along with VirtualServer Route acts as an alternate for mergeable ingress.

Example for VirtualServer:

apiVersion: k8s.nginx.org/v1
kind: VirtualServer
metadata:
  name: cafe
spec:
  host: domain.example.com
  listener:
    http: http-8083
    https: https-8443
  tls:
    secret: sslSecret
  gunzip: on
  upstreams:
  - name: service1
    service: service-file-name
    port: 80
  routes:
  - path: /path1
    action:
      pass: service1

Adding below the table view for detailing each properties.

Example for VirtualServer Routing:

A VirtualServer Route can be considered an equivalent for a kubernetes ingress service. It has advantage of adding multiple subroutes for the main route from VirtualServer and can add additional spec and properties for each subroutes.

apiVersion: k8s.nginx.org/v1
kind: VirtualServerRoute
metadata:
  name: example-virtual-route
  namespace: namespace
spec:
  host: domain.example.com
  upstreams:
  - name: upstream-service-name
    service: service-name
    port: port-number
  subroutes:
  - path: /route/subroute
    action:
      pass: subroute

Handling CORS issues using Virtual-Server:

Below are the annotations added to a kubernetes ingress resource for handling cors resource issue

nginx.ingress.kubernetes.io/enable-cors: "true"
nginx.ingress.kubernetes.io/cors-allow-credentials: "true"

nginx.ingress.kubernetes.io/cors-allow-headers: "X-Forwarded-For"
nginx.ingress.kubernetes.io/cors-allow-methods: "PUT, GET, POST, OPTIONS"
nginx.ingress.kubernetes.io/cors-allow-origin: "*"
nginx.ingress.kubernetes.io/cors-max-age: "seconds"

The equivalent for these annotations in nginx VirtualServer is

responseHeaders:
  add:
    - name: Access-Control-Allow-Credentials
      value: "true"
    - name: Access-Control-Allow-Headers
      value: "X-Forwarded-For"
    - name: Access-Control-Allow-Methods
      value: "PUT, GET, POST, OPTIONS"
    - name: Access-Control-Allow-Origin
      value: "*"
    - name: Access-Control-Max-Age
      value: "seconds"

The above properties will enable the cors actions to be allowed in the resources.