[Kolla] [LetsEncrypt] Internal/External/Backend Certificates

Hi all, another one here that can't seem to get kolla running with letsencrypt certs, just curious as to what settings are required for kolla to pull internal/external/backend certs from letsencrypt? I've looked at the docs and have tried a few settings but keep getting errors, sure i had this working last week before i tore it down ready to deploy for production and now i just cant get it to complete the deployment because of certs, only thing i can think of is i need to run kolla-ansible -i multinode certificates but i thought that was just for self made certs? Also, what are best practices for backend tls certs, self signed or using the internal cert etc?? Is it possible to use letsencrypt at all for backend? Cheers all