====== How to configure mod_proxy_ajp with Tomcat ? ======

<flattr> 
uid=kerphi
title=How to configure mod_proxy_ajp with Tomcat
description=mod_proxy_ajp is an Apache module which can be used to forward a client HTTP request to an internal Tomcat application server using the AJP protocol [...]
category=software
align=right
</flattr>

''mod_proxy_ajp'' is an Apache module which can be used to forward a client HTTP request to an internal Tomcat application server using the [[http://tomcat.apache.org/connectors-doc/ajp/ajpv13a.html|AJP protocol]].

To respond to the question "[[http://tp.its.yale.edu/pipermail/cas/2008-July/009100.html|Why should I use mod_proxy_ajp rather than a classic mod_proxy ?]]", here is a small recap:
  * You can gain a lot of flexibility (lot of the apache modules/features can be used especially "name-based virtual hosting")
  * Practical for those who need to support Java applications along with PHP / Perl ... (only one apache server is needed)
  * Certificates management is easier in apache configuration (this argument is a lot subjective)
  * It's not Tomcat's main objective to serve http static resources (not optimized for that)
  * Load balancing/cluster management is easier with an apache frontend

===== Tomcat configuration =====

You just have to create the AJP connector in the ''conf/server.xml'' file like that:
<code xml>
<Connector port="8009" enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
</code>
This line will enable AJP connections to the 8009 port of your tomcat server (localhost for example).


===== Apache2 configuration =====

One way (useful if this apache is a global front end) is to create a virtual host for this application. 
<code apache> 
Listen 1979
NameVirtualHost *:1979
<VirtualHost *:1979>
   ServerName localhost
   ErrorLog /var/log/apache2/ajp.error.log
   CustomLog /var/log/apache2/ajp.log combined

   <Proxy *>
     AddDefaultCharset Off
     Order deny,allow
     Allow from all
   </Proxy>

   ProxyPass / ajp://localhost:8009/
   ProxyPassReverse / ajp://localhost:8009/
</VirtualHost>
</code>
  * ''ProxyPass'' and ''ProxyPassReverse'' are classic reverse proxy directives used to forward the stream to another location.
  * ''<nowiki>ajp://...</nowiki>'' is the AJP connector location (your tomcat's server host/port)


===== What's the result ? =====

A web client will connect through HTTP to http://localhost:1979/ (supposing your apache2 server is running on localhost), the mod_proxy_ajp will forward you request transparently using the AJP protocol to the tomcat application server on ''localhost:8009''.

{{tag>article computing proxy ajp apache tomcat}}
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