We want to use envoy proxy header x-envoy-downstream-service-cluster to identify source of Microservice call in Kubernetes deployment. For this, we would need to enable the add_user_agent flag by inserting an EnvoyFilter.
Istio documentation has no mention of this header or add_user_agent flag so we don’t know if this is something, we could rely on.
While Istio does support
X-Envoy-External-Address but IPs are ephemeral in Kubernetes env and serve little purpose.
Is add_user_agent not recommended in Istio?