How to install Tomcat on CentOS 7

Alaric Bird

6 years ago

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Follow our comprehensive guide to install Tomcat on CentOS 7. This tutorial covers all the necessary steps, from prerequisites to installation and configuration tips. #centlinux #linux #tomcat

What is Apache Tomcat?

Apache Tomcat is an open-source web server and servlet container developed by the Apache Software Foundation. It implements the Java Servlet, Java Server Pages (JSP), and Java Expression Language (EL) specifications from the Java EE (Enterprise Edition) platform, providing a robust environment for running Java-based web applications. Here’s a detailed look at Apache Tomcat and its features:

Key Features of Apache Tomcat

Servlet and JSP Engine:
- Servlets: Tomcat serves as a Java Servlet container, which processes requests and generates responses for web applications.
- JSP: It supports JavaServer Pages (JSP), a technology for creating dynamic web content.
Open Source:
- Free to Use: Tomcat is open-source software distributed under the Apache License 2.0, making it free to use, modify, and distribute.
High Performance:
- Efficient: Tomcat is designed for high performance and scalability, suitable for handling a range of applications from small-scale projects to large enterprise deployments.
Lightweight:
- Minimal Overhead: It is a lightweight server, focusing on providing a core set of features for web applications without unnecessary overhead.
Modular Architecture:
- Components: Tomcat’s modular architecture includes components like Catalina (Servlet Engine), Jasper (JSP Engine), and Coyote (HTTP Connector).
Clustering and Load Balancing:
- Scalability: Tomcat supports clustering, session replication, and load balancing for high availability and scalability in production environments.
Management and Monitoring:
- Admin Console: Includes a web-based administration console for managing deployments, configurations, and monitoring server status.
- JMX Integration: Supports Java Management Extensions (JMX) for advanced monitoring and management.
IDE Integration:
- Development Tools: Integrates with popular IDEs like Eclipse, IntelliJ IDEA, and NetBeans for streamlined development and deployment.
Security Features:
- Configuration Options: Offers various security features and configuration options, including SSL/TLS support, role-based access controls, and security constraints.

Common Use Cases for Apache Tomcat

Web Applications:
- Deploy and manage Java-based web applications, including e-commerce sites, content management systems, and intranet applications.
Enterprise Solutions:
- Serve as the foundation for enterprise-level Java EE applications, including customer relationship management (CRM) and enterprise resource planning (ERP) systems.
Development and Testing:
- Used by developers for creating and testing Java web applications before deploying them to production environments.

Architecture of Apache Tomcat

Component	Description
Catalina	The servlet container that handles the request/response lifecycle for servlets and JSPs.
Jasper	The JSP engine that compiles JSP pages into servlets.
Coyote	The HTTP connector that listens for incoming requests and forwards them to Catalina.
Cluster	Features for session replication, load balancing, and failover for high-availability setups.
Manager	Web-based application for managing Tomcat’s server and deployed applications.

How Apache Tomcat Compares to Other Servers

Feature	Apache Tomcat	Apache TomEE	WildFly	GlassFish
Servlet Container	Yes	Yes	Yes	Yes
Java EE Support	No	Yes	Yes	Yes
Lightweight	Yes	No	No	No
Enterprise Ready	No	Yes	Yes	Yes
Open Source	Yes	Yes	Yes	Yes

Apache Tomcat Comparison Table

Recommended Online Training: Learn Bash Shell in Linux for Beginners

Application Server Specification

We have provisioned a CentOS 7 virtual machine with following specifications.

Hostname – tomcat-01.example.com
IP Address – 192.168.116.144/24
Operating System – CentOS 7.6
Apache Tomcat – 9

Read Also: How to install TomEE on Linux 7

Install OpenJDK on CentOS 7

Connect with tomcat-01.example.com using ssh as root user.

Apache Tomcat 9 requires Java 8 or later JRE (Java Runtime Environment). Therefore, we will install OpenJDK 8 (an open source implementation of Java platform) on CentOS 7 machine.

# yum install -y java-1.8.0-openjdk-devel

Java executables have been automatically added to PATH environment variable. Therefore, we are only required to set the JAVA_HOME environment variable.

# echo "export JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64" >> /etc/profile
# . /etc/profile
# env | grep JAVA_HOME
JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-1.8.0.191.b12-1.el7_6.x86_64

Verify Java version.

# java -version
openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)

OpenJDK 8 has been installed on our CentOS 7 server.

Note: if you are using more than one Java versions on the same machine then you should read our previous article Install Java on CentOS 7 to perform additional settings using alternatives command.

Install Tomcat on CentOS 7

If we install Apache Tomcat from yum repository, then we do not have to perform following steps manually. But Apache Tomcat 9 is the latest version and it is not yet available in yum repositories. Therefore, we have to install it manually.

Create a user to own Apache Tomcat 9 software.

# useradd -s /sbin/nologin tomcat

Download Apache Tomcat 9 binaries from Tomcat’s website.

# cd
# wget https://www-us.apache.org/dist/tomcat/tomcat-9/v9.0.16/bin/apache-tomcat-9.0.16.tar.gz
--2019-03-03 07:58:26--  https://www-us.apache.org/dist/tomcat/tomcat-9/v9.0.16/bin/apache-tomcat-9.0.16.tar.gz
Resolving www-us.apache.org (www-us.apache.org)... 40.79.78.1
Connecting to www-us.apache.org (www-us.apache.org)|40.79.78.1|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 10783080 (10M) [application/x-gzip]
Saving to: âapache-tomcat-9.0.16.tar.gzâ

100%[======================================>] 10,783,080   414KB/s   in 17s

2019-03-03 07:58:44 (608 KB/s) - âapache-tomcat-9.0.16.tar.gzâ saved [10783080/10783080]

Extract downloaded tarball of Apache Tomcat 9.

# tar xf apache-tomcat-9.0.16.tar.gz

Move extracted directory to /opt/tomcat/.

# mkdir /opt/tomcat
# mv apache-tomcat-9.0.16 /opt/tomcat

Change ownership of /opt/tomcat directory.

# chown -R tomcat:tomcat /opt/tomcat

We will create a soft link latest for /opt/tomcat/apache-tomcat-9.0.16 directory. So, we can upgrade/downgrade Apache Tomcat conveniently.

# ln -s /opt/tomcat/apache-tomcat-9.0.16/ /opt/tomcat/latest

Create a systemd unit file to define a service for Apache Tomcat 9 server.

# vi /usr/lib/systemd/system/tomcat.service

and add following lines therein.

[Unit]
Description=Tomcat 9 servlet container
After=network.target

[Service]
Type=forking

User=tomcat
Group=tomcat

Environment="JAVA_HOME=/usr/lib/jvm/jre"
Environment="JAVA_OPTS=-Djava.security.egd=file:///dev/urandom"

Environment="CATALINA_BASE=/opt/tomcat/latest"
Environment="CATALINA_HOME=/opt/tomcat/latest"
Environment="CATALINA_PID=/opt/tomcat/latest/temp/tomcat.pid"
Environment="CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC"

ExecStart=/opt/tomcat/latest/bin/startup.sh
ExecStop=/opt/tomcat/latest/bin/shutdown.sh

[Install]
WantedBy=multi-user.target

Execute following command to notify systemd that we have created a new unit file.

# systemctl daemon-reload

Start and enable Apache Tomcat service.

# systemctl enable tomcat.service
Created symlink from /etc/systemd/system/multi-user.target.wants/tomcat.service to /usr/lib/systemd/system/tomcat.service.
# systemctl start tomcat.service

Allow Apache Tomcat service port in Linux firewall.

# firewall-cmd --permanent --add-port=8080/tcp
success
# firewall-cmd --reload
success

Browse URL http://tomcat-01.example.com:8080/ in a client’s browser.

It will show the default homepage of Apache Tomcat 9.

Apache Tomcat 9 has been installed on our CentOS 7 server.

Configure Tomcat Application Manager

Application Manager is installed by default with Apache Tomcat 9. Application Manager provides Web UI to easily manage, deploy, start and stop Java applications running on Apache Tomcat 9 server.

But, we need to configure Managers Apps according to our requirement.

Define users and roles to access Apache Tomcat 9 Manager Web UI.

# vi /opt/tomcat/latest/conf/tomcat-users.xml

Add following lines just before </tomcat-users> tag.

   <role rolename="admin-gui"/>
   <role rolename="manager-gui"/>
   <user username="admin" password="admin" roles="admin-gui,manager-gui"/>
   <user username="ahmer" password="123" roles="admin-gui,manager-gui"/>

By default Application Manager is allowed to be accessed from localhost only.

We must edit the following files to let us access it from other machines.

# vi /opt/tomcat/latest/webapps/manager/META-INF/context.xml

Find and comment following lines of code.

  <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127.d+.d+.d+|::1|0:0:0:0:0:0:0:1" />

After comment, it should be looks like this.

<!--
  <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127.d+.d+.d+|::1|0:0:0:0:0:0:0:1" />
-->

Similarly, repeat the above step for following file.

# vi /opt/tomcat/latest/webapps/host-manager/META-INF/context.xml

Restart Apache Tomcat 9 service.

# systemctl restart tomcat.service

Browse URL http://192.168.116.144:8080 using a client’s browser.

Click on Server Status.

Go back and click on Manager App.

Go back and click on Host Manager.

Application Manager has been configured on Apache Tomcat 9 running on CentOS 7 server.

In this article, we will install Apache Tomcat 9 on CentOS 7 and configure Application Manager to perform server administration conveniently. We recommend you to have Tomcat: The Definitive Guide (PAID LINK) by O’Reilly Media as reference during your Apache Tomcat journey.

Final Thoughts

Installing Apache Tomcat on CentOS 7 can set the foundation for robust web applications and services. I hope this guide has provided you with the clear steps needed for a successful installation. If you need additional help or run into any challenges, I’m here to assist you. Check out my Fiverr gig for expert support with Tomcat installations, configurations, and more: Linux Server Support

Feel free to reach out for personalized solutions to ensure your Tomcat setup is done right and efficiently!

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