Ingress with hostname configuration but not automatically created Ingress entities?

[eroji]

We have a Kafka cluster currently using ingress for external access on port 9094. The Kubernetes cluster was previously configured to use Nginx ingress controller with TLS passthrough. I'm now evaluating switching to Traefik for ingress controller as Kubernetes has officially deprecated Nginx. With this, I'm encountering the problem when the listener is configured as ingress type. Strimzi Operator will automatically created the Ingress entities in Kubernetes but to get TLS passthrough to work with Traefik, instead of Ingress, I actually need IngressRouteTCP. The problem then becomes that both Ingress and IngressRouteTCP entities exists in Kubernetes and the client connection isn't routed correctly. To get it to work, I need to have only IngressRouteTCP entities, without Ingress. However, the hostname configuration that is offered by type: ingress is also necessary. I can't see a way to configure Strimzi Operator for this to happen since the hostname configuration is only available for types ingress and route. Manually deleting ingresses created by Strimzi Operator just results in it recreating them.

[scholzj]

Strimzi's Ingress support is written around the TLS-Passthrough and TLS-SNI support in the Ingress controller. Not around any kind of TCP Ingress that is not part of the standard Kubernetes API. So if you want to use the type: ingress listener, you will definitely need to stick with that.

However, you can also self-manage it. You can use type: cluster-ip listener instead. That way, Strimzi will create only the Services. And then you can create your IngressRouteTCP resources your self and configure the advertised addresses in the listener configuration. (https://strimzi.io/docs/operators/latest/full/configuring.html#property-listener-config-broker-reference)

[eroji]

Yes. This is the error I'm seeing.

Listener configuration is not valid: [listener external cannot configure hostTemplate because it is not Route or Ingress based listener, listener external cannot configure bootstrap.host because it is not Route or Ingress based listener]

If I remove the bootstrap hostname, I get this.

Listener configuration is not valid: [listener external cannot configure hostTemplate because it is not Route or Ingress based listener]

This is the configuration I'm using.

...
    - authentication:
        type: scram-sha-512
      configuration:
        hostTemplate: kafka-{nodeId}.namespace.ingress.example.com
        bootstrap:
          host: kafka-bootstrap.namespace.ingress.example.com
      name: external
      port: 9094
      tls: true
      type: cluster-ip

I also tried advertisedHostTemplate and specify individual brokers with advertisedHost. All of them returns with the same error that only route and ingress support configuring host values. Moreover, I'm not sure if it matters but I'm using Strimzi Operator 0.46.1.

[scholzj]

Well, because that is a host template. There is no place where to configure it when you don't use Ingress or Routes. That is why I gave you the link to the advertisedHost docs. That is what you need to set. And you can definitely set it for any listener.

[scholzj]

Regarding the operator version - not sure when the temlate fields were added. You would need to check the docs for given version. But the individual advertisedHost fields are definitely supported in 0.46.1.

[eroji]

Got it. I tried adding the brokers individually and it seems to be working. Thank you.

[scholzj]

Great, glad it works now. I guess the template is maybe not supported yet in 0.46.