Installing Tomcat8 on RHEL6

Apache-HTTP v/s Apache-Tomcat:

The basic difference is Apache-Tomcat is written in Java but Apache-HTTP is written in C. Apart from this Apache-Tomcat is used as a webserver as well as to deploy Java Servlet's and JSP's [Java server pages] so basically Apache-Tomcat is used to serve Java Technologies whereas Apache-HTTP is used to serve HTTP.

Prerequisites:

• Appropriate version of JRE [Java run-time environment] for instance jre1.7 is required to run tomcat-8[.X.X].
• Tomcat binaries, for version 8 check this link.
• Sudo/Root access to the machine.

Step1: Install JRE

• Download JRE from Java's official website.
• You can keep Java at any location but for my ease I have kept both Tomcat and Java in /opt.
• # cd /opt
• # cp jre-7u45-linux-x64.tar.gz .
• # tar -zxvf jre-7u45-linux-x64.tar.gz 
• The above command will create a folder with JRE binaries. In my case it was "jre1.7.0_45".
• Now set JRE_HOME [Required by Tomcat] and PATH.
• export JRE_HOME=/opt/jre1.7.0_45  
• export PATH=$JRE_HOME/bin:$PATH  
• To get this path available to other users we need to get this added in ~/.bashrc or ~/.bash_profile in user's home directory.

Step2: Install Tomcat

• Download the appropriate package [For v8 hyperlink is given above].
• # cd /opt
• # cp apache-tomcat-8.0.0-RC5.tar.gz .
• # tar -zxvf apache-tomcat-8.0.0-RC5.tar.gz
• The above command will create a folder with Tomcat binaries. In my case it was "apache-tomcat-8.0.0-RC5".
• That's it, now you can start your Tomcat via the startup.sh script present in bin directory.
• For instance, my bin directory resides in "/opt/apache-tomcat-8.0.0-RC5/bin" go into this directory and fire "./startup.sh". You will something like given below: 
• Using CATALINA_BASE:   /opt/apache-tomcat-8.0.0-RC5
• Using CATALINA_HOME:   /opt/apache-tomcat-8.0.0-RC5
• Using CATALINA_TMPDIR: /opt/apache-tomcat-8.0.0-RC5/temp
• Using JRE_HOME:        /opt/jre1.7.0_45
• Using CLASSPATH:       /opt/apache-tomcat-8.0.0-RC5/bin/bootstrap.jar:/opt/tomcat/bin/tomcat-juli.jar

There are other scripts also available in that bin directory such as:

• version.sh ==> This shows version of Tomcat being installed and some information about the OS.
• shutdown.sh ==> For shutting down the Tomcat service.
• startup.sh ==> For starting the Tomcat service.
• configtest.sh ==> For checking the configuration etc etc....

Step3: Test your Tomcat server

• Open firefox.
• In the address bar type "localhost:8080" or "DOMAIN:8080" or "IP:8080" and press enter.
• You will see something like given below:

Step4: How to run this Tomcat as a service [ADDITIONAL/OPTIONAL STEP]

• # cd /etc/init.d/
• # vim tomcatd
• Add the following script in this tomcatd file:
• JRE_HOME=/opt/jre1.7.0_45
• export JRE_HOME
• PATH=$JRE_HOME/bin:$PATH
• export PATH  
• CATALINA_HOME=/opt/apache-tomcat-8.0.0-RC5
• case $1 in
• start)
• sh $CATALINA_HOME/bin/startup.sh
• ;;
• stop)
• sh $CATALINA_HOME/bin/shutdown.sh
• ;;
• restart)
• sh $CATALINA_HOME/bin/shutdown.sh
• sh $CATALINA_HOME/bin/startup.sh
• ;;
• esac
• exit 0
• Save and exit from the file via :wq option.
• NOTE: Change JRE_HOME and CATALINA_HOME as per your requirement.
• # chmod 755 tomcatd [Change its permissions].
• Now test your script via:
• # service tomcatd start
• # service tomcatd stop
• # service tomcatd restart

WHERE TO CHECK FOR LOGS:

• # cd $CATALINA_HOME/logs
• # tail -f catalina.out