Installing Apache and Tomcat on CentOS4

This HowTo will discuss how to install Apache and Tomcat on CentOS4. And if the title isn’t self explanatory enough we will be using mod_jk to link Apache and Tomcat.

1. Let’s install Apache to start…

shell> yum install httpd

2. Now let’s download the Java JDK from http://java.sun.com/javase/downloads/index.jsp (It is labeld as JDK 6u1)

• After clicking on Download we are going to look for “Linux Platform – Java(TM) SE Development Kit 6 Update 1″
• Download the “Linux RPM in self-extracting file” the filename should be jdk-6u1-linux-i586-rpm.bin

shell> mkdir -p /usr/java/
shell> mv jdk-6u1-linux-i586-rpm.bin /usr/java
shell> chmod a+x /usr/java/jdk-6u1-linux-i586-rpm.bin
shell> /usr/java/jdk-6u1-linux-i586-rpm.bin
shell> ln -s /usr/java/jdk1.6.0_01 /usr/java/jdk

3. Next let’s download the following packages from http://archive.apache.org/dist/tomcat/tomcat-5/archive/v5.5.9/bin/ (Tomcat 5.5.9 used for this set of instructions)

• jakarta-tomcat-5.5.9-admin.tar.gz
• jakarta-tomcat-5.5.9.tar.gz

shell> tar xzvf jakarta-tomcat-5.5.9-admin.tar.gz
shell> tar xzvf jakarta-tomcat-5.5.9.tar.gz
shell> mv jakarta-tomcat-5.5.9 /usr/java/tomcat

4. We can now setup an init script for Tomcat

• Download catalina to /etc/init.d

shell> chmod a+x catalina
shell> chkconfig –add catalina
shell> chkconfig catalina on

5. Now we need to install the Tomcat Apache connector

• Download mod_jk from http://mirrors.dotsrc.org/jpackage/1.6/redhat-el-4.0/free/RPMS/mod_jk-ap20-1.2.15-1jpp.i386.rpm

shell> rpm -Uvh mod_jk-ap20-1.2.15-1jpp.i386.rpm

6. Edit the workers.properties file in /usr/java/tomcat/conf

workers.tomcat_home=/usr/java/tomcat
workers.java_home=/usr/java/jdk
workers.list=ajp13
worker.ajp13.host=[fully qualified domain name]
worker.ajp13.cachesize=20
worker.loadbalancer.balanced_workers=ajp13

7. Edit the server.xml file in /usr/java/tomcat/conf

• Immediately below the entry <Server port=”8005″ shutdown=”SHUTDOWN”> add:

<Listener className=”org.apache.jk.config.ApacheConfig”
modJk=”/usr/lib/httpd/modules/mod_jk.so”
workersConfig=”/usr/java/tomcat/conf/workers.properties”
jkLog=”/usr/java/tomcat/logs/mod_jk.log” jkDebug=”info” />

• Find the entry <Host name=”localhost” appBase=”webapps” unpackWARs=”true” autoDeploy=”true” xmlValidation=”false” xmlNamespaceAware=”false”> and change localhost to your fully qualified domain name or IP address.
• This is also how you would define Tomcat virtual hosts. I won’t go into detail about virtual hosting with Tomcat. If you are interested in virtual hosting with Tomcat I suggest checking out some search results on Google.

<Host name=”[fully qualified domain name]” appBase=”webapps”
unpackWARs=”true” autoDeploy=”true”
xmlValidation=”false” xmlNamespaceAware=”false”>

• Immidiately following that line add:

<Listener className=”org.apache.jk.config.ApacheConfig” append=”true” jkWorker=”ajp13″ />

8. Let’s now start up Tomcat. From the configuration changes made above Tomcat will generate an Apache conf file that will be used to load the Tomcat info.

shell> /etc/init.d/catalina start

9. Now we need to do a few quick things for Apache to work with Tomcat.

shell> ln -s /usr/java/tomcat/conf/auto/mod_jk.conf /etc/httpd/conf.d/
shell> /etc/init.d/httpd start

10. Let’s give it a test

• Open a web browser and navigate to http://[hostname]/jsp-examples

Side Notes: As you notice above, Tomcat is installed in /usr. /usr is usually not one of the larger partitions on a web server. In the past I have created a directory /var/www/tomcat, copied the contents of /usr/java/tomcat/webapps to /var/www/tomcat, delete webapps and then create a symlink from /var/www/tomcat to /usr/java/tomcat/webapps. I also recommend creating a directory /var/log/tomcat, deleting /usr/java/tomcat/logs and creating a symlink from /var/log/tomcat to /usr/java/tomcat/logs. Use your best judgment as to how you want to handle this.