repeated string hosts = 1;

  // secretName is the name of the secret used to terminate TLS traffic on
  // port 443. Field is left optional to allow TLS routing based on SNI
  // hostname alone. If the SNI host in a listener conflicts with the "Host"
  // header field used by an IngressRule, the SNI host is used for termination
  // and value of the "Host" header is used for routing.
  // +optional
  optional string secretName = 2;
}

  repeated string hosts = 1;

  // secretName is the name of the secret used to terminate TLS traffic on
  // port 443. Field is left optional to allow TLS routing based on SNI
  // hostname alone. If the SNI host in a listener conflicts with the "Host"
  // header field used by an IngressRule, the SNI host is used for termination
  // and value of the Host header is used for routing.
  // +optional
  optional string secretName = 2;

  repeated string hosts = 1;

  // SecretName is the name of the secret used to terminate SSL traffic on 443.
  // Field is left optional to allow SSL routing based on SNI hostname alone.
  // If the SNI host in a listener conflicts with the "Host" header field used
  // by an IngressRule, the SNI host is used for termination and value of the
  // Host header is used for routing.
  // +optional
  optional string secretName = 2;
}

`IstioOperatorSpec` has pass-through fields to the Helm values.yaml API, but these are additionally validated through
a [schema](../operator/pkg/apis/istio/v1alpha1/values_types.proto).
1. [Controller](#k8s-controller) code. The code comprises the K8s listener, webhook and logic for reconciling the cluster
to an `IstioOperatorSpec` CR.
1. [Manifest creation](#manifest-creation) code. User settings are overlaid on top of the