Application (ingress, service and deployment) lives in one namespace but the add-on proxy lives in another

[tonsV2]

I install by executing the below commands

helm repo add kedacore https://kedacore.github.io/charts
helm repo update

helm install keda kedacore/keda --namespace keda --create-namespace

helm install http-add-on kedacore/keda-add-ons-http --namespace keda

I then deploy the application I want to scale along with a HTTPScaledObject in another namespace. However I can't point its ingress to the keda-add-ons-http-interceptor-proxy running in the keda namespace because they're not in the same namespace.

I tried to install the add-on into multiple namespaces but that fails with the below error message

tons@p1 ~/I/d/im-tooling (main)> helm install http-add-on-dhis2 kedacore/keda-add-ons-http --namespace dhis2 --skip-crds
Error: INSTALLATION FAILED: Unable to continue with install: CustomResourceDefinition "httpscaledobjects.http.keda.sh" in namespace "" exists and cannot be imported into the current release: invalid ownership metadata; annotation validation error: key "meta.helm.sh/release-name" must equal "http-add-on-dhis2": current value is "http-add-on-keda"; annotation validation error: key "meta.helm.sh/release-namespace" must equal "dhis2": current value is "keda"

What's the way to go about this?

[tonsV2]

It seems like the answer is to create another service which points to the keda proxy in the other namespace. Such a service would be of type ExternalName since it's referencing a service running in a different namespace. While Nginx does support this, Traefik doesn't which for some people might be a deal breaker.

Yet another solution which I haven't tried would be to use Gateway API rather than a regular Ingress since that can reference services in other namespaces by default. However The Gateway API isn't bundled with most Kubernetes distributions by default so that's something most users would have to install manually.