istio service entry example

ServiceEntry allow us to register service to Istio so that istio would be able to route it correctly. In this example, we will take a request from a client and then forwards it to an external service entry called "portquiz.net". 

So let's create a service entry, virtual service and ingress gateway

apiVersion: networking.istio.io/v1

kind: ServiceEntry

metadata:

  name: portquiz-net

spec:

  hosts:

  - portquiz.net

  location: MESH_EXTERNAL

  ports:

  - number: 80

    name: http

    protocol: HTTP

  resolution: DNS

---

apiVersion: networking.istio.io/v1

kind: Gateway

metadata:

  name: example-gateway

spec:

  selector:

    istio: ingressgateway # use the default Istio ingress

  servers:

  - port:

      number: 80

      name: http

      protocol: HTTP

    hosts:

    - "*"

---

apiVersion: networking.istio.io/v1

kind: VirtualService

metadata:

  name: forward-to-example

spec:

  hosts:

  - "*" # accept any host (localhost)

  gateways:

  - example-gateway

  http:

  - match:

    - uri:

        prefix: /

    rewrite:

      uri: /  

    route:

    - destination:

        host: portquiz.net

        port:

          number: 80

     

The configuration is quite simple. The only catch is the portquiz.net or any other host for that matter

will tend to look for host headers too.

So we need to pass this information along

curl -v -H "Host: portquiz.net" http://localhost:80

We will get output "Port test successful" as shown below:-

And then doing a log of our ingress

kubectl logs istio-ingressgateway-6c5b69ccf5-jl6nb -n istio-system -f

We will get similiar outputs:-