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External Service

Expose a service located outside the Kubernetes cluster using an Ingress.

Before you begin ensure that you have Installed Kong Ingress Controller with Gateway API support in your Kubernetes cluster and are able to connect to Kong.

Prerequisites

Install the Gateway APIs

Install the Gateway API CRDs before installing Kong Ingress Controller.

 kubectl apply -f https://github.com/kubernetes-sigs/gateway-api/releases/download/v1.1.0/standard-install.yaml

Create a Gateway and GatewayClass instance to use.

echo "
---
apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: kong
  annotations:
    konghq.com/gatewayclass-unmanaged: 'true'

spec:
  controllerName: konghq.com/kic-gateway-controller
---
apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: kong
spec:
  gatewayClassName: kong
  listeners:
  - name: proxy
    port: 80
    protocol: HTTP
" | kubectl apply -f -

The results should look like this:

gatewayclass.gateway.networking.k8s.io/kong created
gateway.gateway.networking.k8s.io/kong created

Install Kong

You can install Kong in your Kubernetes cluster using Helm.

Add the Kong Helm charts:

 helm repo add kong https://charts.konghq.com
 helm repo update

Install Kong Ingress Controller and Kong Gateway with Helm:

 helm install kong kong/ingress -n kong --create-namespace 

Test connectivity to Kong

Kubernetes exposes the proxy through a Kubernetes service. Run the following commands to store the load balancer IP address in a variable named PROXY_IP:

Populate $PROXY_IP for future commands:

 export PROXY_IP=$(kubectl get svc --namespace kong kong-gateway-proxy -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
 echo $PROXY_IP

Ensure that you can call the proxy IP:

 curl -i $PROXY_IP

The results should look like this:

 HTTP/1.1 404 Not Found
 Content-Type: application/json; charset=utf-8
 Connection: keep-alive
 Content-Length: 48
 X-Kong-Response-Latency: 0
 Server: kong/3.0.0
  
 {"message":"no Route matched with those values"}

Create a Kubernetes Service

Deploy a Kubernetes Service type=ExternalName using the hostname of the application you want to expose.

 echo "
 kind: Service
 apiVersion: v1
 metadata:
   name: proxy-to-httpbin
 spec:
   ports:
   - protocol: TCP
     port: 80
   type: ExternalName
   externalName: httpbin.konghq.com
 " | kubectl apply -f -

The results should look like this:

 service/proxy-to-httpbin created

Create an Ingress to expose the service at the path /httpbin

Gateway API

Ingress

echo "
apiVersion: gateway.networking.k8s.io/v1
kind: HTTPRoute
metadata:
  name: proxy-from-k8s-to-httpbin
  annotations:
    konghq.com/strip-path: 'true'
spec:
  parentRefs:
  - name: kong
  rules:
  - matches:
    - path:
        type: 
        value: /httpbin
    backendRefs:
    - name: proxy-to-httpbin
      kind: Service
      port: 80
" | kubectl apply -f -

echo "
apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: proxy-from-k8s-to-httpbin
  annotations:
    konghq.com/strip-path: 'true'
spec:
  ingressClassName: kong
  rules:
  - http:
      paths:
      - path: /httpbin
        pathType: ImplementationSpecific
        backend:
          service:
            name: proxy-to-httpbin
            port:
              number: 80
" | kubectl apply -f -

The results should look like this:

      Gateway API
    
      Ingress
    
httproute.gateway.networking.k8s.io/proxy-from-k8s-to-httpbin created
ingress.networking.k8s.io/proxy-from-k8s-to-httpbin created

Test the Service

curl -i $PROXY_IP/httpbin/anything

The results should look like this:

HTTP/1.1 200 OK
Date: Thu, 15 Dec 2022 21:31:47 GMT
Content-Type: application/json
Content-Length: 341
Connection: keep-alive
Server: gunicorn/19.9.0
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true
X-Kong-Upstream-Latency: 2
X-Kong-Proxy-Latency: 1
Via: kong/3.1.1

{
  "args": {},
  "data": "",
  "files": {},
  "form": {},
  "headers": {
    "Accept": "*/*",
    "Host": "httpbin.konghq.com",
    "User-Agent": "curl/7.86.0",
    "X-Amzn-Trace-Id": "Root=1-639b9243-7cdb670008b8189a5948d619"
  },
  "json": null,
  "method": "GET",
  "origin": "136.25.153.9",
  "url": "https://httpbin.konghq.com/anything"
}