change Nginx Configuration path in ubuntu Docker

I new change my nginx Configuration path like
/etc/nginx/nginx.conf to /opt/nginx_agent/conf/nginx.conf

so i follow this link http://serverfault.com/questions/821284/how-can-i-change-nginx-configuration-file-path to Configure this, But, "While Reload the Daemon Process"

"systemctl daemon-reload"

its throw `Failed to connect to bus: No such file or directory` so, follow this [link](http://stackoverflow.com/questions/39169403/systemd-and-systemctl-within-ubuntu-docker-images) they suggest `Since systemd isn't running as init inside your container, there's no daemon to process your start and stop commands.`

So, I need to Change nginx Configuration path, suggest me How to do that.