How to Install Apache Tomcat 9 on Ubuntu 18.04

Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, and Java Expression Language technologies. It powers numerous large-scale, mission-critical web applications across various industries and sectors. This tutorial will guide you through the process of installing Apache Tomcat 9 on Ubuntu 18.04.

Prerequisites

• Ubuntu 18.04 server instance.
• A user account with sudo privileges.
• Java Development Kit (JDK) installed on your system.
• Basic knowledge of Linux command line.

Main Steps

Follow the steps below to install Apache Tomcat 9 on your Ubuntu 18.04 server:

Step 1: Install Java Development Kit (JDK)

Before installing Tomcat, ensure that you have JDK installed on your system. You can install OpenJDK with the following commands:

sudo apt update
sudo apt install default-jdk

After the installation is complete, verify the Java installation:

java -version

You should see the installed version of Java in the output.

Step 2: Create a Tomcat User

It is a good practice to run Tomcat as its own user. Create a new user for Tomcat with the following command:

sudo useradd -r -m -U -d /opt/tomcat -s /bin/false tomcat

Step 3: Download Tomcat 9

Navigate to the /tmp directory to download the Apache Tomcat tar.gz file:

cd /tmp
curl -O https://dlcdn.apache.org/tomcat/tomcat-9/v9.0.62/bin/apache-tomcat-9.0.62.tar.gz

Extract the downloaded archive:

sudo tar xzvf apache-tomcat-9.0.62.tar.gz -C /opt/tomcat --strip-components=1

Step 4: Change Ownership

Change the ownership of the Tomcat directory to the tomcat user:

sudo chown -R tomcat: /opt/tomcat

Step 5: Configure Systemd for Tomcat

Create a systemd service file for Tomcat to manage it as a service:

sudo nano /etc/systemd/system/tomcat.service

Paste the following content into the file:

[Unit]
Description=Apache Tomcat Web Application Container
After=network.target

[Service]
Type=simple
User=tomcat
Group=tomcat
Environment=JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/opt/tomcat/bin/shutdown.sh

[Install]
WantedBy=multi-user.target

Step 6: Start Tomcat Service

Reload systemd to apply the changes and then start the Tomcat service:

sudo systemctl daemon-reload
sudo systemctl start tomcat
sudo systemctl enable tomcat

Step 7: Adjust Firewall Settings

If you are using a firewall, allow traffic on port 8080:

sudo ufw allow 8080/tcp

Step 8: Access Tomcat Web Interface

Open your web browser and visit http://your_server_ip:8080. You should see the Tomcat welcome page.

Advanced Configuration

Once Tomcat is installed, you may want to configure it for specific needs:

Changing Default Port

To change the default port Tomcat runs on, edit the server.xml file:

sudo nano /opt/tomcat/conf/server.xml

Look for the following line:

<Connector port="8080" protocol="HTTP/1.1" ... />

Change the port number to your desired port and save the file.

Setting Up Users for Manager App

You can set up users to access the Tomcat Manager app. Open the tomcat-users.xml file:

sudo nano /opt/tomcat/conf/tomcat-users.xml

Add the following lines within the <tomcat-users> tags:

<role rolename="manager-gui"/>
<user username="admin" password="your_password" roles="manager-gui"/>

Replace your_password with a secure password.

Best Practices

• Keep your Tomcat installation up to date to avoid security vulnerabilities.
• Regularly back up your Tomcat configuration and web applications.
• Monitor Tomcat performance and logs for any issues.
• Use a reverse proxy (like Nginx or Apache HTTP Server) in front of Tomcat for better security and performance.

Troubleshooting

If you encounter issues starting the Tomcat service, check the logs located in /opt/tomcat/logs.

• Use sudo systemctl status tomcat to check the service status.
• Review catalina.out for any errors.

Conclusion

In this tutorial, we covered the steps to install Apache Tomcat 9 on Ubuntu 18.04. By following these instructions, you should have a functional Tomcat server ready for hosting Java applications. Remember to configure your installation according to your security needs and performance requirements.

This HTML document provides a comprehensive tutorial on how to install Apache Tomcat 9 on Ubuntu 18.04, including prerequisites, main steps, advanced configurations, best practices, troubleshooting, and conclusion, ensuring that users can easily follow through the installation process.