How To Install and Configure Apache Tomcat on a Debian Server

Introduction

Apache Tomcat is an application server that can be used to serve Java applications to web users. It is an open implementation of the Java Servlet and JavaServer Pages specs that were developed by Sun Microsystems.
If you develop Java applications, Tomcat is a quick and easy way to serve them in a full server environment specifically designed for that purpose.
In this guide, we will install Tomcat and do some basic configuration on a Debian 7 VPS. To complete this tutorial, you will have to have a normal user with sudo privileges. Follow this guide to learn how to create users on a Debian system.

Install Apache Tomcat

In this guide, we will install Tomcat version 8 and its associated packages. Luckily, these are included in the default Debian repositories.
To get the basic package, we can update our package source list and then install the main package:

sudo apt-get update
sudo apt-get install tomcat8

This is all we need to do to get to the default Tomcat page. Our installation is not complete yet, but you can take a look at the default Tomcat page by going to your IP address or domain followed by :8080 in your web browser:

your_domain_or_ip:8080 

In order to take advantage of more of Tomcat's features, we will install some additional Tomcat packages.
These will allow us to use a web interface to control Tomcat. It will install some documentation and examples that we can also access through the web interface as well.

sudo apt-get install tomcat8-admin tomcat8-examples tomcat8-docs

The Tomcat documentation also suggests that you install Apache Ant, which is a build tool for Java applications, and a version control system of some sort. We will choose git:

sudo apt-get install ant git

These will help you build your Java applications and keep the code organized.

Configure Tomcat Web Interface

Before we can begin using some of the features we installed, we need to configure our server with a user and password. Tomcat does not do this by default for security reasons.
The configuration is very simple. We need to edit a file called tomcat-users.xml. Open it with an editor like this:

sudo nano /etc/tomcat8/tomcat-users.xml

Inside, you will find a heavily commented user configuration file. In fact, the only portions of the file that are not comments are:

<tomcat-users>
</tomcat-users>

As you might expect, we need to define a user between these two lines. We will give this user access to the web interfaces. We can define a user like this:

<tomcat-users>
    <user username="admin" password="password" roles="manager-gui,admin-gui"/>
</tomcat-users>

Choose whatever username and password you would like. This will provide you with login credentials that allow you to access the management panels.
Save and close the file when you are finished.
We should restart Tomcat in order to implement our changes:

sudo service tomcat8 restart

 We should stop Tomcat  to implement our changes:

sudo service tomcat8 stop 

Test the Web Interface

Once you have installed Tomcat and configured the user login, you can access the main page by going to your server IP address or domain name followed by :8080 like this:

your_domain_or_ip:8080

You will see the same default Tomcat page that you saw earlier (if you checked):