How to access OpenStack Dashboard installed in a headless Ubuntu server using conjure-up

After I finished installing OpenStack using Ubuntu's conjure-up on a single machine, I found myself struggle to access the dashboard. The only machine that can access the OpenStack Dashboard is the host server which is a headless Ubuntu server. It's because conjure-up installs OpenStack by deploy its components to multiple containers with a virtual private network that connects those services. So in order to access the dashboard from outside, I had to create an iptable rule that NAT the OpenStack Dashboard container's http port (443 or 80) to a host server's port (443 properly). Here is an example:

sudo iptables -t nat -A PREROUTING -p tcp -d <ip of the host server> --dport 443 -j DNAT --to-destination <internal ip of the openstack dashboard service, usually 10.x.x.x>:443

After that, I was able to access the OpenStack web interface from other machines.