AGC Gateway fails when one of multiple Listeners has problems - Seeking multi-app configuration

Question

Hi there,

I'm trying some first tenous steps in using Application Gateway for Container (AGC) in order to make multiple different applications running in my AKS accessible from the internet.

I use the ALB Controller which manages the Application Gateway Resources. I've defined a Gateway using multiple Listeners using individual certificates (supplied by a cert-manager)

Spec:
  Addresses:
    Type:              Hostname
    Value:             bga9d2fqf6a6bqef.fz52.alb.azure.com
  Gateway Class Name:  azure-alb-external
  Listeners:
    Allowed Routes:
      Namespaces:
        From:  All
    Name:      http-listener
    Port:      80
    Protocol:  HTTP
    Allowed Routes:
      Namespaces:
        From:  All
    Hostname:  host1.whatever.com
    Name:      my-listener1
    Port:      443
    Protocol:  HTTPS
    Tls:
      Certificate Refs:
        Group:
        Kind:   Secret
        Name:   cert-a
      Mode:     Terminate
    Allowed Routes:
      Namespaces:
        From:  All
    Hostname:  host2.whatever.com
    Name:      my-listener2
    Port:      443
    Protocol:  HTTPS
    Tls:
      Certificate Refs:
        Group:
        Kind:   Secret
        Name:   cert-b
      Mode:     Terminate

Then I can deploy some HttpRoutes in order to route the traffic to my deployed pods.

Now I've stumbled about a behaviour which irritates me massively. Whenever there is something wrong with one listener the whole gateway fails.

If I (for the sake of demonstration) delete the secret/cert-b, I'd expect the domain host2.whatever.com to be unreachable while the othe domain/listener for host1.whatever.com continues to work. But what reallyhappens is that the Gateway stops working completely, when it has issues with one listener.

From my point of view this is a strange behaviour and unless solved prevents me from using AGC as described in this scenario.

Is there another way to configure one gateway to connect multiple apps / pods to the outside without having this kind of single point of failure?

Any thoughts / ideas are appreciated!!!

Regards,
Bastian