Nginx forward to another server

location /path_1/ {
proxy_pass http://internal_host:port/;
}

http://external_server/path_1/whatever?p=xxx
--->
http://internal_server:port/whatever?p=xxx

https://serverfault.com/questions/699695/nginx-proxy-pass-remove-url-substring

location ~* ^/service/(.*) {
proxy_pass http://apache/$1$is_args$args;
}