How to update FQDN through API (v1)

Hi, I’m building a simple CLI application that does the following:

  • Use Rancher API v1 (Rancher 1.1.4) to get all loadbalancers
  • Get public-ip and ports for loadbalancer
  • Get service and stack/environment name for loadbalancer
  • Generate / Update / Delete Nginx (external reverse proxy) conf file to listen for server_name as generated in the next bullet and set upstreams pointing to the loadbalancer.
  • Update DNS record in corporate intranet DNS service (Infoblox) resulting in: <service_name>

My question is: How can I update the FQDN field of loadbalancers or services in Rancher through the v1 API?

The API docs make me believe the service.fqdn or loadbalancerservice.fqdn are read only? Though external dns services from the catalog seem to update the values if I read the docs right?

(I cant use catalog entries due to an offline no-internet on-premise install of Rancher)

(If I get this to work, what is the use for the internal Rancher loadbalancers? I could also just do this for services with external ports and Nginx would be my loadbalancer right?)