Introduction

This article discusses how to install and configure Apache 2.0.x and Tomcat (or JBoss) to communicate with each other via mod_jk. This article also discusses how to setup a Tomcat cluster using mod_jk to balance work load.

Install JDK

1. Download JDK rpm and launch the executable by running the following commands:

   chmod a+x j2sdk-1_4_2_<version number>-linux-i586-rpm.bin
   ./j2sdk-1_4_2_<version number>-linux-i586-rpm.bin

2. Type yes and agree to the binary license agreement.
3. Become root by running su and entering root password
4. Install the rpm. This will install JDK at /usr/java/j2sdk-1.4.2:

   rpm -iv jdk-1.4.2_<version number>.i386.rpm

5. Edit PATH environment variable to include bin directory of JDK by adding the following lines to /etc/profile:

   JAVA_HOME=/usr/java/j2sdk-1.4.2_<version number>
   export JAVA_HOME
   PATH=$JAVA_HOME/bin:$PATH

Avoid Firewall and Routing issues

1. Disable the default firewall (unless you can configure it to allow multicast packets)

   /etc/init.d/iptables stop
   /etc/init.d/ip6tables stop

2. Add this multicast route:

   /sbin/route add -net 224.0.0.0 netmask 240.0.0.0 dev eth<id>

Install Apache

1. Download httpd-2.0.50-i686-pc-linux-gnu.tar.gz into a temporary location and run the following commands to install Apache at /usr/local/share:

   unzip < httpd-2.0.50-i686-pc-linux-gnu.tar.gz | tar xvf -
   cd httpd-2.0.50
   ./install-bindist.sh /usr/local/share/apache-2.0.50

2. Edit PATH environment variable to include bin directory of Apache by adding the following lines to /etc/profile:

   APACHE_HOME=/usr/local/share/apache-2.0.50
   export APACHE_HOME
   PATH=$APACHE_HOME/bin:$PATH
   export PATH

Install Tomcat

1. Move apache-tomcat-x.y.z.zip.zip to /usr/local/share (I will refer to the installation folder by this path) and unzip it:

   unzip apache-tomcat-x.y.z.zip

2. Edit PATH environment variable to include bin directory of Apache by adding the following lines to /etc/profile:

   TOMCAT_HOME=/usr/local/share/apache-tomcat-x.y.z
   export TOMCAT_HOME
   PATH=$TOMCAT_HOME/bin:$PATH
   export PATH

Configure mod_jk

1. Copy the mod_jk binary to $APACHE_HOME/modules directory and rename it as mod_jk.so
2. Add the following lines at the very bottom in $APACHE_HOME/conf/httpd.conf
   
   

   #Include mod_jk configuration file
   Include conf/mod-jk.conf

3. Under $APACHE_HOME/conf create mod-jk.conf and write the following lines in it:
   
   

   # Load mod_jk module
   # Specify the filename of the mod_jk lib
   LoadModule jk_module modules/mod_jk.so
   # Where to find workers.properties
   JkWorkersFile conf/workers.properties
   # Where to put jk logs
   JkLogFile logs/mod_jk.log
   # Set the jk log level [debug/error/info]
   JkLogLevel info
   # Select the log format
   JkLogStampFormat "[%a %b %d %H:%M:%S %Y]"
   # JkOptions indicates to send SSK KEY SIZE
   JkOptions +ForwardKeySize +ForwardURICompat -
   ForwardDirectories
   # JkRequestLogFormat
   JkRequestLogFormat "%w %V %T"
   JkMount /Context/* loadbalancer

   
   
   Where Context is the web-app context name.

4. Under $APACHE_HOME/conf create workers.properties and populate it as follows:
   
   

   # Worker list
   worker.list=loadbalancer
   # Define Node1
   worker.node1.port=8009
   worker.node1.host=node1.ip.address
   worker.node1.type=ajp13
   worker.node1.lbfactor=1
   #worker.node1.local_worker=1 (1)
   worker.node1.cachesize=10
   # Define Node2
   worker.node2.port=8009
   worker.node2.host=node2.ip.address
   worker.node2.type=ajp13
   worker.node2.lbfactor=1
   #worker.node2.local_worker=1 (1)
   worker.node2.cachesize=10
   # Load-balancer
   worker.loadbalancer.type=lb
   worker.loadbalancer.balanced_workers=node1, node2
   worker.loadbalancer.sticky_session=1
   worker.loadbalancer.local_worker_only=1

   Add one worker per node and name workers as node1, node2, node3 … nodeN. Don’t forget to define all these as load balancing workers:

   worker.loadbalancer.balanced_workers=node1, node2, node3, ... nodeN

   Replace node1.ip.address with IPAddress of Tomcat(or JBoss) instance1 and so on. The attribute sticky_session=1 tells mod_jk that SESSION ID’s should be routed back to the same Tomcat worker. The lbfactor determines the number of requests a worker receives. The higher the lbfactor the more requests a worker receives.

5. Each node should be named according to the names specified in workers.properties. On each Tomcat instance, edit $TOMCAT_HOME/conf/server.xml. Locate the <Engine> element and add an attribute called jvmRoute:

   <Engine name="Catalina" defaultHost="localhost" jvmRoute="node1">
   …
   </Engine>

NOTE: THE jvmRoute ATTRIBUTE MUST MATCH THE NAME SPECIFIED IN workers.properties.

Start Apache and Tomcat

1. Start Apache:

   $APACHE_HOME/bin/apachectl -k start

2. To stop use:

   $APACHE_HOME/bin/apachectl -k stop

3. Start Tomcat:

   $TOMCAT_HOME/bin/startup.sh

4. Stop Tomcat:

   $TOMCAT_HOME/bin/shutdown.sh

Introduction

This article discusses how to configure Apache and OpenSSL to serve https content. We assume Apache is installed and OpenSSL commands are available in the PATH environment variable. Otherwise install Apache and OpenSSL using yum or apt.

Create a working directory

Let’s call it sslcert:

$mkdir sslcert

Create two subdirectories under it

Create 2 subdirectories under sslcert. Let’s call them certs and private.

$cd sslcert
$mkdir certs private

Create a database to keep track of each certificate signed

Run the following commands:

$echo '01' > serial
$touch certindex.txt

Make a custom config file for openssl to use

Copy the config elements into a file called openssl.cnf. (edit as needed):