Docker:
The reverse proxy cannot obtain the correct IP address
Consider adding a script to import local resolver from /etc/resolv.conf
Nginx:
Nginx with dynamic upstreams
Using DNS for Service Discovery with NGINX and NGINX Plus
NGINX Plus: Load Balancing – Service Discovery Using DNS
Configuring HTTP Load Balancing Using DNS
Module ngx_http_upstream_module – resolver
openresty resolv.conf parsing