How to mask a tomcat app behind an apache subdomain? - apache

Question

I have two separate servers: an Apache public server and an internal Tomcat one. I would like our users to be able to use our Tomcat apps without exposing the details of our implementation (actual port, server name, context) through the public Apache server like this:
http://credits.publicdomain.com/servlet
instead of
http://tomcat.internaldomain.com:8082/CreditsApp/servlet
How can I configure my Apache server to mask requests to our Tomcat apps this way? Is using Apache modules such as mod_rewrite or mod_proxy the most straightforward approach?
I have tried this configuration for a VirtualHost in Apache, which works for the first servlet. However it seems to disable Tomcat to keep the session from the first servlet to any other servlet you go afterwards:
ServerName credits.publicdomain.com
ProxyRequests Off
ProxyPreserveHost On
<Proxy *>
Order deny,allow
Allow from all
</Proxy>
ProxyPass / http://tomcat.internaldomain.com:8082/CreditsApp/
ProxyPassReverse / http://tomcat.internaldomain.com:8082/CreditsApp/
Am I missing some additional configuration in my Tomcat server in order to work without the context between servlets?

Answer 1

The best and most efficient way to do this is using mod_jk: http://tomcat.apache.org/connectors-doc/
I've used this in several projects and found it to be extremely easy to use, effective, flexible, and performant. It's also the de facto official solution to stacking Tomcat behind Apache.

Answer 2

mod_jk is what you need to bridge Tomcat to Apache, so you can focus on your app
and Apache, as the front-end, can deal with https and authentication and such. It will forward certain URLs to 'workers' in Tomcat. So you need to tell Apache to load the mod_jk, you need to configure worker.properties, Apache would need to know which worker does what, and you need to define a Service in Tomcat.
These directives in httpd.conf configure mod_jk:
JKWorkersFile conf/workers.properties
JKLogFile /var/log/tomcat/mod_jk.log
JKLogLevel info
The JKWorkersFile in /etc/httpd/conf/workers.properties basically defines sockets
workers.tomcat_home=/var/tomcat4
workers.java_home=/usr/java/jdk
ps=/
worker.list=worker1,worker2
worker.worker1.port=8009
worker.worker1.host=localhost
worker.worker1.type=ajp13
worker.worker2.port=8010
worker.worker2.host=localhost
worker.worker2.type=ajp13
This snippet for httpd.conf would delegate everything (i.e. /* ) to worker1:
<VirtualHost 192.0.34.72>
ServerAdmin webmaster# example.com
DocumentRoot /www/www.example.com/webapps/ROOT
ServerName www.example.com
ErrorLog logs/public_errors
LogLevel debug
CustomLog logs/public_access combined
JkMount /* worker1
<Directory "/www/www. example.com/webapps/ROOT">
Options Indexes FollowSymLinks Indexes
AllowOverride None
Order allow,deny
Allow from all
</Directory>
<Location "/WEB-INF/">
AllowOverride None
deny from all
</Location>
<Location "/META-INF/">
AllowOverride None
deny from all
</Location>
</VirtualHost>
And Tomcat would have this service:
<service name="public">
<connector classname="org.apache.coyote.tomcat4.CoyoteConnector" port="8009" minprocessors="5" maxprocessors="75" enablelookups="true" redirectport="8443" acceptcount="10" debug="0" connectiontimeout="0" useurivalidationhack="false" protocolhandlerclassname="org.apache.jk.server.JkCoyoteHandler" />
<engine name="Standalone" defaulthost="localhost" debug="0">
<logger classname="org.apache.catalina.logger.FileLogger" prefix="catalina_log." suffix=".txt" timestamp="true" /> <realm classname="org.apache.catalina.realm.UserDatabaseRealm" debug="0" resourcename="UserDatabase" /> 
<host name="localhost" debug="0" appbase="/www/www.example.com/webapps" unpackwars="true" autodeploy="true">
<logger classname="org.apache.catalina.logger.FileLogger" directory="logs" prefix="localhost_log." suffix=".txt" timestamp="true" />
</host>
</engine>
</service>
The above examples are from my notes, check update documentation at:
http://tomcat.apache.org/connectors-doc/generic_howto/workers.html
http://tomcat.apache.org/connectors-doc/webserver_howto/apache.html