Red Hat Application Server: JOnAS User Guide
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Chapter 44. Setting Up mod_jk with embedded Tomcat

NoteNote
 

Replace ${JONAS_BASE} and ${APACHE_HOME} with appropriate values.

  1. Open the file $JONAS_BASE/conf/server.xml and uncomment the following line:

    <!--
<Connector port="9009" enableLookups="false"
    redirectPort="9043" debug="0"
    protocol="AJP/1.3" />
-->

    Edit it to look like the following:

    <Connector port="9009" enableLookups="false"
    redirectPort="9043" debug="0"
    protocol="AJP/1.3" />

  2. Now you can either let tomcat generate the mod_jk.conf file automatically, which will setup forwarding for a limited set of applications, or you can create a custom mod_jk.conf file. The automatically generated file cannot be customized since it is re-written every time tomcat is restarted by the user.

    1. To enable automatic generation insert the following into the server.xml file nested under the base <Server> tag:

      <Listener className="org.apache.jk.config.ApacheConfig"
    modJk="$APACHE_HOME/modules/mod_jk.so" />

      and insert the following under the <Host> element:

      <Listener className="org.apache.jk.config.ApacheConfig"
    append="true" forwardAll="false"
    modJk="$APACHE_HOME/modules/mod_jk.so"/>

      When jonas/tomcat is restarted, there will be a file created under $JONAS_BASE/conf/auto called mod_jk.conf.

    2. If you want to create a custom file, the recommendation is to place mod_jk.conf under $JONAS_BASE/conf/jk. A simple mod_jk.conf file that can be used is:

      # Load the mod_jk module if not loaded.
<IfModule !mod_jk.c>
LoadModule jk_module "$APACHE_HOME/modules/mod_jk.so"
</IfModule>

# Specify location of worker file and log file.
# Worker file will follow shortly.
JkWorkersFile "$JONAS_BASE/conf/jk/workers.properties"
JkLogFile "$JONAS_BASE/logs/mod_jk.log"

# When and how much logging.
JkLogLevel emerg

# This is a little awkward. It seems mod_jk associates 
# applications that map to tomcat based on the virtual host. 
# If, for instance, I wish to visit the jonasAdmin application 
# through http://jonas-server/jonasAdmin from another machine 
# and I have the following setting then the application behaves
# perfectly normally; that is, struts kicks in as expected, 
# form-based authentication and forwarding is done exactly as 
# expected if you were using the application directly using 
# the appropriate port (9000). However, if you try using 
# http://localhost/jonasAdmin from jonas-server without the 
# explicit VirtualHost declaration, only the directory contents
# are mapped. So we need to explicitly mention both virtual hosts.
<VirtualHost jonas-server>
    ServerName jonas-server
    JkMount /olstore ajp13
    JkMount /olstore/* ajp13
    JkMount /jonasAdmin ajp13
    JkMount /jonasAdmin/* ajp13
</VirtualHost>
# ajp13 is in fact the worker name used in workers.properties.
<VirtualHost localhost>
    ServerName localhost
    JkMount /olstore ajp13
    JkMount /olstore/* ajp13
    JkMount /jonasAdmin ajp13
    JkMount /jonasAdmin/* ajp13
</VirtualHost>

  3. To tell apache to use this file, edit the $APACHE_HOME/conf/httpd.conf file and insert:

    Include ${JONAS_BASE}/conf/jk/mod_jk.conf

    NoteNote
     

    Replace ${JONAS_BASE} with appropriate value.

  4. Create a workers.properties file. This can be placed in $JONAS_ROOT/conf/jk/workers.properties.

    A sample that has been used successfully is:

    # workers.java_home should point to your Java installation. 
# Normally you should have a /bin and a /lib beneath it.
#
workers.java_home=/usr/lib/jvm/java

#
# You should configure your environment slash... ps=\ on NT 
# and / on UNIX and possibly something different elsewhere.
#
ps=/

#
#------ ADVANCED MODE -------------------------------------
#----------------------------------------------------------
#

#
#------ DEFAULT worker list -------------------------------
#----------------------------------------------------------
#
#
# The workers that your plugins should create and work with
#
# Add 'inprocess' if you want a JNI connector
worker.list=ajp13
# , inprocess

#
#------ DEFAULT worker1 WORKER DEFINITION -----------------
#----------------------------------------------------------
#

#
#!
Defining a worker named worker1 and of type worker1
# Note that the name and the type do not have to match.
#
worker.ajp13.port=9009
worker.ajp13.host=jonas-server
worker.ajp13.type=ajp13

#----------------------------------------------------------

  5. Once all this is completed, restart httpd and ensure that jonas/tomcat is up. You can follow that up with a quick test by visiting http://host_name/jonasAdmin. You should now be able to use the application as normal.

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