HA chef-server network setup

Hi all,

I'm new to chef and trying to setup HA chef-server. The document(https://docs.chef.io/install_server_ha/) is pretty straightforward and I've set it up without any issues.

My question is about network port requirement between frontend group to backend cluster. I like to put a load balancer between frontend group and backend cluster. So when the backend cluster node's ip changes, I don't have to update frontend node configuration. Will this kind of setup break the network between frontend and backend? If it's fine to use a loadbalancer, does it need to forward all elasticsearch ports(9200 - 9300) from the network requirement in below? Since the diagram in same document only mentions 5432 and 9200 port.

Inbound from frontend group to backend cluster
TCP 2379 (etcd)
TCP 5432 (PostgreSQL)
TCP 7331 (leaderl)
TCP 9200-9300 (Elasticsearch)

Thanks for the help!