Apache & JBoss use port 80 at the same time

Question

I have both Apache 2 and JBoss 4.2.3 on the same machine and would like both of them to use port 80. There are several ways I see people doing this mod_jk, mod_proxy, but I'm not sure which one is the best.

I don't need any load balancing, but I do need HTTPS.

Answer 1

You can't have two applications listening to the same tcp port (80) at the same time. You can use mod_jk to have http requests on port 80 routed from Apache server to the JBoss server. This is the method I am most familiar with and prefer. mod_proxy should also work, but I find that method a little more complicated.

Configuring https on Apache is probably best dealt with as a separate topic. There are issues with purchasing a ssl certificate, creating a self-signed certificate, etc.

There are two steps to accomplish configure mod_jk to route requests from the Apache server to the JBoss server:

Configure the Apache web server to forward some requests to the JBoss server.

The Apache configuration will vary depending on the distribution of Apache that you are using (windows, RHEL, debian, built from source, etc.) but the concepts should be similar for any Apache installation.

You need to download mod_jk for your platform from the tomcat web site:
http://tomcat.apache.org/download-connectors.cgi
Your OS vendor may provide a binary for you, so check there first. You may also compile mod_jk yourself if you prefer.

Copy the mod_jk binary (mod_jk.so for Linux/UNIX system, not sure about windows) into your Apache servers modules directory (this depends on the Apache distribution you are using).

Add the equivalent directive to your Apache configuration:

LoadModule jk\_module /usr/lib/apache2/modules/mod\_jk.so

You should add two configuration files to the Apache configuration directory: mod_jk.conf and workers.properties. You should include mod_jk.conf from the main Apache configuration file:

Include /etc/apache2/mod\_jk.conf

The workers.properties file is included by mod_jk.conf with the JkWorkersFile directive.

More detailed settings for mod_jk.conf can be found at the tomcat documentation page:
http://tomcat.apache.org/connectors-doc/reference/apache.html

The important directives are:
JkWorkersFile (specifies where the workers.properties file lives)
JkMount (mount point for mapping of URI to tomcat worker)

An example:

JkWorkersFile /etc/apache2/workers.properties<br>
JkMount  /examples/*  myworker<br>
JkMount  /examples    myworker

These directives map the /examples and /examples/ URI to the myworker tomcat worker.

Conceptually you can think of a worker as representing a tomcat or JBoss instance and the mount as a way of mapping a URI to a worker. This way of representing things allows one Apache server to be the front end for several tomcat or JBoss servers. This can be handy if you have only one IP address you can use but wish to run several application servers behind one Apache server.

The workers.properties files describes the tomcat or JBoss server(s) that the Apache server will connect to. Important entries in this file are:

worker.list=myworker<br>
worker.tomcat.type=ajp13<br>
worker.tomcat.host=localhost<br>
worker.tomcat.port=8009

There are other worker properties that can be found in the tomcat documentation page for the workers.properties file:
http://tomcat.apache.org/connectors-doc/reference/workers.html

Configure the JBoss server to accept connections from the Apache server

The JBoss server is configured to accept mod_jk connections on port 8009 (the default ajp port) out of the box, but it is good to know where to configure this in case you want to change any of this in the future.

The configuration is in the tomcat based portion of the JBoss server located in ${JBOSS_SERVER_CONFIGURATION}/deploy/jbossweb.sar/server.xml. This is for JBoss AS 5.1.0.GA, previous versions are in a similar location. The mod_jk connector is configured in the Connector section for the AJP 1.3 protocol and looks like:

<Connector protocol="AJP/1.3" port="8009" address="${jboss.bind.address}"    redirectPort="8443" />

The most common reason to modify this section is if you have multiple tomcat or JBoss servers connecting to apache via the AJP protocol, you can adjust the port number that the AJP connector will listens on so there are no conflicts.