Red Hat APPLICATION SERVER - JONAS Manual page 245

Chapter 32. Clustering with JOnAS
32.2.1. Configuring the JK Module (mod_jk)
32.2.1.1. JK module principles
is a plug-in that handles the communication between Apache and Tomcat.
mod_jk
uses the concept of a worker. A worker is a Tomcat instance that is running to perform Servlet
mod_jk
requests coming from the web server. Each worker is identified to the web server by the host on which
it is located, the port where it listens, and the communication protocol used to exchange messages. In
this configuration there is one worker for each Tomcat instance and one worker that will handle the
load balancing (this is a specific worker with no host and no port number). All workers are defined in
the
worker.properties
Note:
The JK Module can also be used for site partitioning.
32.2.1.2. Configure Apache
• httpd.conf
Create a file
$APACHE_HOME/conf/httpd.conf
LoadModule jk_module libexec/mod_jk.so
AddModule mod_jk.c
Next, configure
mod_jk
# Location of the worker file
JkWorkersFile "/etc/httpd/conf/jk/workers.properties"
# Location of the log file
JkLogFile "/etc/httpd/jk/logs/mod_jk.log"
# Log level : debug, info, error or emerg
JkLogLevel emerg
# Assign specific URL to Tomcat workers
JkMount /admin loadbalancer
JkMount /admin/* loadbalancer
JkMount /examples loadbalancer
JkMount /examples/* loadbalancer
worker.properties
•
This file should contain the list of workers first:
worker.list=a_comma-separated_list_of_worker_names
then the properties of each worker:
worker.worker name.property;=property_value
The following is an example of a
# List the workers name
worker.list=worker1,worker2,loadbalancer
# ----------------
# First worker
# ----------------
worker.worker1.port=8009
worker.worker1.host=server1
worker.worker1.type=ajp13
# Load balance factor
file.
named
tomcat_jk.conf
. This file loads the module
:
worker.properties
, which must
:
mod_jk
file:
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be included in