Updated to add proxy permissions and single site config

Writing this as I ran into a couple of issues when setting up Apache as a front-end web server for a Amazon EC2 instance running two applications in Play, which I wanted to address from different domains with no port. The Play instructions are ok, but miss a couple of small things that tripped up a newb like me (not loading proxy http module or giving full path to modules).

1. Install apache - sudo apt-get install apache2

2. Enable http_proxy module - sudo a2enmod proxy_http

3. Update apache2.conf - sudo vim /etc/apache2/apache2.conf

with the following:

<VirtualHost *:80>
ProxyPreserveHost On
ServerName mydomainheadheader1.com
ProxyRequests off
<proxy *>
Order deny,allow
Allow from all
</proxy>
ProxyPass /excluded !
ProxyPass / http://127.0.0.1:9000/
ProxyPassReverse / http://127.0.0.1:9000/
</VirtualHost>

<VirtualHost *:80>
ProxyPreserveHost On
ServerName 

mydomainheadheader2.com
ProxyRequests off
<proxy *>
Order deny,allow
Allow from all
</proxy>
ProxyPass /excluded !
ProxyPass / http://127.0.0.1:81/
ProxyPassReverse / http://127.0.0.1:81/
</VirtualHost>

If you are only proxying for a single site you don't need a VirtualHost, just (will forward all requests on port 80 to the proxy):

ProxyRequests Off
ProxyPreserveHost On
<Proxy *>
Order allow,deny
Allow from all
</Proxy>

ProxyPass / http://127.0.0.1:9000/
ProxyPassReverse / http://127.0.0.1:9000/

4. Restart apache - sudo /etc/init.d/apache2 restart

The two sites hosted on your server should now be accessible from the domains.

If you muck up, errors should be logged in /var/log/apache2/error.log.