<p><strong>Brief of the problem</strong>:</p>

<ul>
<li>If I try to attach multiple TLS gateways (using the same certificate)
to one ingressgateway, only one TLS will work. (The last applied)</li>
<li>Attaching multiple non-TLS gateways to the same ingressgateway works ok.</li>
</ul>

<p><strong>Error messages</strong>:</p>

<p>Domain 1 (ok):</p>

<pre><code>✗ curl -I https://integration.domain.com
HTTP/2 200 
server: envoy
[...]
</code></pre>

<p>Domain 2 (bad):</p>

<pre><code>✗ curl -vI https://staging.domain.com    
* Rebuilt URL to: https://staging.domain.com/
*   Trying 35.205.120.133...
* TCP_NODELAY set
* Connected to staging.domain.com (35.x.x.x) port 443 (#0)
* ALPN, offering h2
* ALPN, offering http/1.1
* Cipher selection: ALL:!EXPORT:!EXPORT40:!EXPORT56:!aNULL:!LOW:!RC4:@STRENGTH
* successfully set certificate verify locations:
*   CAfile: /etc/ssl/certs/ca-certificates.crt
  CApath: /etc/ssl/certs
* TLSv1.2 (OUT), TLS header, Certificate Status (22):
* TLSv1.2 (OUT), TLS handshake, Client hello (1):
* Unknown SSL protocol error in connection to staging.domain.com:443 
* Curl_http_done: called premature == 1
* stopped the pause stream!
* Closing connection 0
curl: (35) Unknown SSL protocol error in connection to staging.domain.com:443 
</code></pre>

<p><strong>Facts</strong>:</p>

<p>I have a wildcard TLS cert (lets say '*.domain.com') I've put in a secret with:</p>

<pre><code>kubectl create -n istio-system secret tls istio-ingressgateway-certs --key tls.key --cert tls.crt
</code></pre>

<p>I have the default istio-ingressgateway attached to a static IP: </p>

<pre><code>apiVersion: v1
kind: Service
metadata:
  name: istio-ingressgateway
  namespace: istio-system
  annotations:
  labels:
    chart: gateways-1.0.0
    release: istio
    heritage: Tiller
    app: istio-ingressgateway
    istio: ingressgateway
spec:
  loadBalancerIP: "35.x.x.x"
  type: LoadBalancer
  selector:
    app: istio-ingressgateway
    istio: ingressgateway
[...]
</code></pre>

<p>Then I have two gateways in different namespaces, for two domains included on the TLS wildcard (staging.domain.com, integration.domain.com):</p>

<p>staging:</p>

<pre><code>apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: domain-web-gateway
  namespace: staging
spec:
  selector:
    istio: ingressgateway # use Istio default gateway implementation
  servers:
  - port:
      number: 443
      name: https
      protocol: HTTPS
    tls:
      mode: SIMPLE
      serverCertificate: /etc/istio/ingressgateway-certs/tls.crt
      privateKey: /etc/istio/ingressgateway-certs/tls.key
    hosts:
    - "staging.domain.com"
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "staging.domain.com"
</code></pre>

<p>integration:</p>

<pre><code>apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: domain-web-gateway
  namespace: integration
spec:
  selector:
    istio: ingressgateway # use Istio default gateway implementation
  servers:
  - port:
      number: 443
      name: https
      protocol: HTTPS
    tls:
      mode: SIMPLE
      serverCertificate: /etc/istio/ingressgateway-certs/tls.crt
      privateKey: /etc/istio/ingressgateway-certs/tls.key
    hosts:
    - "integration.domain.com"
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "integration.domain.com"
</code></pre>

<p>The problem is that you are using the same name (https) for port 443 in two Gateways managed by the same workload (selector). They need to have unique names. This restriction is documented <a href="https://preliminary.istio.io/help/ops/traffic-management/deploy-guidelines/#configuring-multiple-tls-hosts-in-a-gateway" rel="nofollow noreferrer">here</a>.</p>

<p>You can fix it by just changing the name of your second Gateway, for example:</p>

<pre><code>apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
  name: domain-web-gateway
  namespace: integration
spec:
  selector:
    istio: ingressgateway # use Istio default gateway implementation
  servers:
  - port:
      number: 443
      name: https-integration
      protocol: HTTPS
    tls:
      mode: SIMPLE
      serverCertificate: /etc/istio/ingressgateway-certs/tls.crt
      privateKey: /etc/istio/ingressgateway-certs/tls.key
    hosts:
    - "integration.domain.com"
  - port:
      number: 80
      name: http
      protocol: HTTP
    hosts:
    - "integration.domain.com"
</code></pre>
