Istio + Kubernetes: Gateway more than one TLS Certificate - ssl

Question

I have a Kubernetes cluster with multiple tenants (in different namespaces). I'd like to deploy an independent Istio Gateway object into each tenant, which I seem to be able to do. However, setting up TLS requires a K8s secret that contains the TLS key/cert. The docs indicate that the "secret must be named istio-ingressgateway-certs in the istio-system namespace". This would seem to indicate that I can only have one TLS secret per cluster. Maybe I'm not reading this correctly. Is there a way to configure independent Istio Gateways in their own namespaces, with their own TLS secrets? How might I go about doing that?
Here is the doc that I'm referencing.
https://istio.io/docs/tasks/traffic-management/ingress/secure-ingress-mount/
Any thoughts are much appreciated.

Answer 1

As provided on istio documentation it's possible.
In this section you will configure an ingress gateway for multiple hosts, httpbin.example.com and bookinfo.com.
So You need to create private keys, in this example, for bookinfo and httbin, and update istio-ingressgateway.
I created them both and they exist.
bookinfo certs and gateway
kubectl exec -it -n istio-system $(kubectl -n istio-system get pods -l istio=ingressgateway -o jsonpath='{.items[0].metadata.name}') -- ls -al /etc/istio/ingressgateway-bookinfo-certs
lrwxrwxrwx 1 root root 14 Jan 3 10:12 tls.crt -> ..data/tls.crt
lrwxrwxrwx 1 root root 14 Jan 3 10:12 tls.key -> ..data/tls.key
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: bookinfo-gateway
spec:
selector:
istio: ingressgateway # use istio default ingress gateway
servers:
- port:
number: 443
name: https-bookinfo
protocol: HTTPS
tls:
mode: SIMPLE
serverCertificate: /etc/istio/ingressgateway-bookinfo-certs/tls.crt
privateKey: /etc/istio/ingressgateway-bookinfo-certs/tls.key
hosts:
- "bookinfo.com"
httpbin certs and gateway
kubectl exec -it -n istio-system $(kubectl -n istio-system get pods -l istio=ingressgateway -o jsonpath='{.items[0].metadata.name}') -- ls -al /etc/istio/ingressgateway-certs
lrwxrwxrwx 1 root root 14 Jan 3 10:07 tls.crt -> ..data/tls.crt
lrwxrwxrwx 1 root root 14 Jan 3 10:07 tls.key -> ..data/tls.key
apiVersion: networking.istio.io/v1alpha3
kind: Gateway
metadata:
name: httpbin-gateway
spec:
selector:
istio: ingressgateway # use istio default ingress gateway
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:
- "httpbin.example.com"
Haven't made a full reproduction to check if they both works but if that won't work for You i will try to make it and update the question.
This link might be helpful.