Odoo 12. Configure dbfilter to associate sub-domains to instances
I would like to connect a sub-domain to each of my Odoo 12 instances so as the user can see only the respective instance that is associated with the subdoamain (no Database selector). I have two instances, "erp1" and "erp2" and also a domain "example.com". I am trying to associate erp1.example.com to the instance "erp1" and erp2.example.com to the instance "erp2"
I have installed Odoo 12 on Ubuntu 18.04 server (DigitalOcean) with Nginx and Let's Encrypt SSL certificate. Although the domain/IP works fine with the Nginx (no need to add default port, 8069) unfortunately, I am not able to filter the sub-domains.
There numerous guides and posts online however, none works for me. Can someone describe the steps/process I need to follow and the files (including paths) that I need to configure so as the dbfilter work?