Hi in case you want to to have you Nodejs server in a container, here are the following things you need to do

create a docker-compose.yml with envoy and node docker file

version: '3'
services:
 envoy:
  //setup
 node-app:
  //setup 

change the following line in envoy.yaml

hosts: [{ socket_address: { address: host.docker.internal, port_value: 8080 }}]

to

hosts: [{ socket_address: { address: node-app, port_value: 8080 }}]

I have not tested this but I think this should be enough. Let me know if I missed something.