How to solve 'upstream connect error or disconnect/reset before headers. reset reason: connection termination' in Istio?
I encountered the same error but with a different issue. The Service port needed a name added to it. https://github.com/istio/istio/issues/19966. And they need to follow the format (protocol-suffix) https://istio.io/docs/ops/deployment/requirements/

ports:
    - name: https # Use http or https
       protocol: TCP
       port: 8080
       targetPort: 8080