Kubernetes NGINX Ingress TLS issue

Question

I deployed k8s cluster in cloud (VMVare vSphere) - 3 masters and 1 worker node. Then with helm installed nginx-ingress:

helm install stable/nginx-ingress

Deployed few pods of simple http-svc

Changed nginx-controller service type from LoadBalancer to NodePort and added externalIPs (IP adressess of my master nodes), so it's look like:

NAME                                TYPE        CLUSTER-IP      EXTERNAL-IP                              PORT(S)                       AGE
ing-nginx-ingress-controller        NodePort    10.233.15.202   172.16.40.21,172.16.40.22,172.16.40.23   80:31045/TCP,443:31427/TCP    1d
http-svc                            ClusterIP   10.233.13.55                                             80/TCP                        1d

Created certificate and secret

openssl req -x509 -nodes -days 365 -newkey rsa:2048 -keyout /tmp/tls.key -out /tmp/tls.crt -subj "/CN=<FQDN_HERE>"
kubectl create secret tls secret --key /tmp/tls.key --cert /tmp/tls.crt

And created ingress:

apiVersion: extensions/v1beta1
kind: Ingress
metadata:
  name: some-ingress
  namespace: default
spec:
  tls:
  - hosts:
    - <FQDN_HERE>
    secretName: secret
  rules:
  - host: <FQDN_HERE>
    http:
      paths:
      - backend:
          serviceName: http-svc
          servicePort: 80
        path: /

If i using a cloud DNAT

external_ip:8443 -> master01_ip:443 (e.g. 172.16.40.21:443)

Then i have a response:

curl --resolve <FQDN>:8443:<external_ip> https://<FQDN>:8443 -v -k
* Added <FQDN>:8443:<external_ip> to DNS cache
* Rebuilt URL to: https://<FQDN>:8443/
* Hostname <FQDN> was found in DNS cache
*   Trying <external_ip>...
* TCP_NODELAY set
* Connected to <FQDN> (<external_ip>) port 8443 (#0)
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* TLSv1.2 (OUT), TLS header, Certificate Status (22):
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Server hello (2):
* TLSv1.2 (IN), TLS handshake, Certificate (11):
* TLSv1.2 (IN), TLS handshake, Server key exchange (12):
* TLSv1.2 (IN), TLS handshake, Server finished (14):
* TLSv1.2 (OUT), TLS handshake, Client key exchange (16):
* TLSv1.2 (OUT), TLS change cipher, Client hello (1):
* TLSv1.2 (OUT), TLS handshake, Finished (20):
* TLSv1.2 (IN), TLS change cipher, Client hello (1):
* TLSv1.2 (IN), TLS handshake, Finished (20):
* SSL connection using TLSv1.2 / ECDHE-RSA-AES256-GCM-SHA384
* ALPN, server accepted to use http/1.1
* Server certificate:
*  subject: CN=<FQDN>
*  start date: Feb 22 10:37:00 2018 GMT
*  expire date: Feb 22 10:37:00 2019 GMT
*  issuer: CN=<FQDN>
*  SSL certificate verify result: self signed certificate (18), continuing anyway.
> GET / HTTP/1.1
> Host: <FQDN>:8443
> User-Agent: curl/7.58.0

But if i using Load Balancing feature (vEdge Gateway):

                -> 172.16.40.21:443
external_ip:443 -> 172.16.40.22:443
                -> 172.16.40.23:443

There is a problem:

curl --resolve <FQDN>:443:<external_ip> https://<FQDN> -vvvv -k
* Added <FQDN>:443:<external_ip> to DNS cache
* Rebuilt URL to: https://<FQDN>/
* Hostname <FQDN> was found in DNS cache
*   Trying <external_ip>...
* TCP_NODELAY set
* Connected to <FQDN> (<external_ip>) port 443 (#0)
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* TLSv1.2 (OUT), TLS header, Certificate Status (22):
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to <FQDN>:443
* Closing connection 0
curl: (35) OpenSSL SSL_connect: SSL_ERROR_SYSCALL in connection to <FQDN>:443

Tried two standalone VMs with nginx and self-signed cert - worked as expected. Cloud provider says LB is functional and problem in k8s ingress.

Thanks!

LB should be configured in TCP mode, not HTTP one. Does vEdge Gateway support this? — nickgryg
@Nickolay thank you for your answer. Yes, vEdge Gateway supports TCP load balancing, and i configured it. And it worked! But there is caveats about port. I cannot use 443 for external IP (vEdge bug or misconfiguration). I need some time for questioning support about this and testing. — Andrey Okhotnikov

Andrey Okhotnikov Andrey Okhotnikov · Accepted Answer · 2018-02-28T08:36:14

As @Nickolay said i should had configured HTTPS mode vEdge Gateway Load Balancer in TCP mode. But vEdge Gateway doesn't allow this because port 443 strictly bound to HTTPS. I resolved my problem with configure Health Check (!) to TCP instead of SSL, and all working by now.

Kubernetes NGINX Ingress TLS issue

1 Answers