Configuring https redirect

This guide walks through how to configure the Kubernetes Ingress Controller to redirect HTTP request to HTTPS so that all communication from the external world to your APIs and microservices is encrypted.

Installation

Please follow the deployment documentation to install the Kubernetes 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.

Setup a Sample Service

For the purpose of this guide, we will setup an httpbin service in the cluster and proxy it.

kubectl apply -f https://bit.ly/k8s-httpbin
service/httpbin created
deployment.apps/httpbin created

Create an Ingress rule to proxy the httpbin service we just created:

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

Test the Ingress rule:

$ curl -i $PROXY_IP/foo/status/200
HTTP/1.1 200 OK
Content-Type: text/html; charset=utf-8
Content-Length: 0
Connection: keep-alive
Server: gunicorn/19.9.0
Date: Wed, 17 Jul 2019 19:25:32 GMT
Access-Control-Allow-Origin: *
Access-Control-Allow-Credentials: true
X-Kong-Upstream-Latency: 2
X-Kong-Proxy-Latency: 1
Via: kong/3.1.1

Setup HTTPS redirect

To instruct Kong to redirect all HTTP requests matching this Ingress rule to HTTPS, update its annotations to limit its protocols to HTTPS only and issue a 308 redirect:

$ kubectl patch ingress demo -p '{"metadata":{"annotations":{"konghq.com/protocols":"https","konghq.com/https-redirect-status-code":"308"}}}'
ingress.extensions/demo patched

Test it

Now, making a plain-text HTTP request to Kong will result in a redirect being issued from Kong:

$ curl $PROXY_IP/foo/headers -I
HTTP/1.1 308 Permanent Redirect
Date: Tue, 06 Aug 2019 18:04:38 GMT
Content-Type: text/html
Content-Length: 167
Connection: keep-alive
Location: https://35.197.125.63/foo/headers
Server: kong/1.2.1

The Location header will contain the URL you need to use for an HTTPS request. Please note that this URL will be different depending on your installation method. You can also grab the IP address of the load balancer fronting Kong and send a HTTPS request to test it.

Let’s test it:

$ curl -k https://35.197.125.63/foo/headers
{
  "headers": {
    "Accept": "*/*",
    "Connection": "keep-alive",
    "Host": "35.197.125.63",
    "User-Agent": "curl/7.54.0",
    "X-Forwarded-Host": "35.197.125.63"
  }
}

We can see that Kong correctly serves the request only on HTTPS protocol and redirects the user if plaint-text HTTP protocol is used. We had to use -k flag in cURL to skip certificate validation as the certificate served by Kong is a self-signed one. If you are serving this traffic via a domain that you control and have configured TLS properties for it, then the flag won’t be necessary.

If you have a domain that you control but don’t have TLS/SSL certificates for it, please check out Using cert-manager with Kong guide which can get TLS certificates setup for you automatically. And it’s free, thanks to Let’s Encrypt!