using-external-service.md

Expose an external application

This example shows how we can expose a service located outside the Kubernetes cluster using an Ingress.

Installation

Please follow the deployment documentation to install Kong Ingress Controller on your Kubernetes cluster.

Testing Connectivity to Kong

This guide assumes that the PROXY_IP environment variable is set to contain the IP address or URL pointing to Kong. Please follow one of the deployment guides to configure this environment variable.

If everything is setup correctly, making a request to Kong should return HTTP 404 Not Found.

$ curl -i $PROXY_IP
HTTP/1.1 404 Not Found
Date: Fri, 21 Jun 2019 17:01:07 GMT
Content-Type: application/json; charset=utf-8
Connection: keep-alive
Content-Length: 48
Server: kong/1.2.1

{"message":"no Route matched with those values"}

This is expected as Kong does not yet know how to proxy the request.

Create a Kubernetes service

First we need to create a Kubernetes Service type=ExternalName using the hostname of the application we want to expose.

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

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

echo '
apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: proxy-from-k8s-to-httpbin
  annotations:
    konghq.com/strip-path: "true"
    kubernetes.io/ingress.class: kong
spec:
  rules:
  - http:
      paths:
      - path: /foo
        backend:
          serviceName: proxy-to-httpbin
          servicePort: 80
' | kubectl create -f -

Test the service

$ curl -i $PROXY_IP/foo