Hosting multiple MarkLogic app servers on port 80

Hosting more than one MarkLogic site on a server can be tricky to the uninitiated in Apache configuration.  This is not my area of expertise by any means; so given that I had to figure it out yesterday after once again forgetting how it works I think I’ll write it down here for the next time I need it.  Each MarkLogic application server listens on a different high numbered port.  Given the potential of draconian firewalls rules for both your hosting provider and users, typically the only reliable HTTP port will be 80.  Here’s what I do on Linux and Mac OSX (sorry Windows):

• Set up my MarkLogic machine in cloud hosting (I’ve used both Amazon EC2 and Rackspace) or on on a spare machine with a dependable internet connection / power supply.

• Running 40GB instances of MarkLogic in production is now free with the MarkLogic Express License.  Woot!

• Register .com with a hosting provider or a domain registry
• The hosting provider usually will have a website where I can edit my DNS rules
• Create an A rule for and direct it to my ML machine’s IP

• Create a second A rule for and direct it to the ML machine’s IP

• On the ML machine, install Apache2 and edit the /etc/apache2/httpd.conf file to load the following modules (add to the end of the LoadModule section if it isn’t loaded already):

LoadModule proxy_module /usr/lib/apache2/modules/mod_proxy.so
LoadModule proxy_http_module /usr/lib/apache2/modules/mod_proxy_http.so

• Add the following virtual host records to the very bottom of the file

NameVirtualHost *
<VirtualHost *>
ServerName subdomain1.domain.com
ProxyRequests Off
    <Proxy *>
        Order deny,allow
        Allow from all
    </Proxy>

    ProxyPass / http://localhost:9001/
    ProxyPassReverse / http://localhost:9001/
    <Location />
        Order allow,deny
        Allow from all
    </Location>
</VirtualHost>

<VirtualHost *>
ServerName subdomain2.domain.com
ProxyRequests Off
    <Proxy *>
        Order deny,allow
        Allow from all
    </Proxy>

    ProxyPass / http://localhost:9002/
    ProxyPassReverse / http://localhost:9002/
    <Location />
        Order allow,deny
        Allow from all
    </Location>
</VirtualHost>

• When done editing the file restart Apache2 with the following command:

sudo /usr/sbin/apachectl restart