How to install Apache Tomcat on CentOS 7

In this article I describe in a nutshell how to install Apache Tomcat on CentOS 7 Linux box, the version of Apache is 8.5.24. The steps that I cover are the following:

1. Install Java
2. Download Apache Tomcat using wget
3. Set permissions 
4. Set system unit file
5. Install haveged 
6. Setup firewall exclusions 
7. Configure the xml files

1.- Install Java

Run the following commands to update your system and install Java if needed

yum -y update

yum -y install epel-release

yum install java-1.8.0-openjdk.x86_64

2.- Download Apache Tomcat using wget

Create the location from where Apache Tomcat will run (/opt/tomcat/, also called Catalina's home) and also create a dedicate non-root user for the service

mkdir /opt/tomcat

groupadd tomcat

useradd -s /bin/nologin -g tomcat -d /opt/tomcat tomcat

 While on the /opt/ folder , download Apache Tomcat (we are going to be using version 8.5.25) from this link:

wget http://www.mirrorservice.org/sites/ftp.apache.org/tomcat/tomcat-8/v8.5.28/bin/apache-tomcat-8.5.28.tar.gz

tar -zxvf apache-tomcat-8.5.28.tar.gz -C /opt/tomcat --strip-components 1

//**by using the "--stript-components 1" you're untaring the .gz file at the root of opt/tomcat

3.- Set permissions

Set the proper permissions before running the service

chgrp -R tomcat conf

chmod g+rwx conf

chmod g+r conf/*

chown -R tomcat logs/ temp/ webapps/ work/

chgrp -R tomcat bin

chgrp -R tomcat lib

chmod g+rwx bin

chmod g+r bin/*

4.- Set system unit file

 You need to setup as well a system unit file for Apache Tomcat service

vi /etc/systemd/system/tomcat.service

//**populate the above file with:

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

[Service]
Type=forking

Environment=JAVA_HOME=/usr/lib/jvm/jre
Environment=CATALINA_PID=/opt/tomcat/temp/tomcat.pid
Environment=CATALINA_HOME=/opt/tomcat
Environment=CATALINA_BASE=/opt/tomcat
Environment='CATALINA_OPTS=-Xms512M -Xmx1024M -server -XX:+UseParallelGC'
Environment='JAVA_OPTS=-Djava.awt.headless=true -Djava.security.egd=file:/dev/./urandom'

ExecStart=/opt/tomcat/bin/startup.sh
ExecStop=/bin/kill -15 $MAINPID

User=tomcat
Group=tomcat

[Install]
WantedBy=multi-user.target

5.- Install haveged

Install as well the security related program haveged, and make sure it starts at system boot together with Tomcat

yum install haveged

systemctl start haveged.service

systemctl enable haveged.service

systemctl start tomcat.service

systemctl enable tomcat.service

6.- Setup firewall exclusions 

Add the exception on your firewall zone (trusted on my example) to access port 8080

firewall-cmd --zone=trusted --permanent --add-port=8080/tcp

firewall-cmd --reload

At this stage, you should be able to open Apache Tomcat from the loopback IP address at the CentOS server: http://127.0.0.1:8080

We still need to give access to the computers on your LAN to access the Apache Tomcat interface, which is what I need on my case

7.- Configure the xml files 

Visit the location /opt/tomcat/conf/ and either edit or create the file tomcat-users.xml as follows: 

<role rolename="manager-gui"/>
<role rolename="manager"/>
<role rolename="manager-status"/>
<role rolename="manager-script"/>
<role rolename="manager-jmx"/>
<role rolename="admin-gui"/>
<role rolename="admin"/>
<user username="admin" password="password1" roles="manager-gui,manager,
manager-status,manager-script,manager-jmx,admin-gui,admin"/>

Visit the locations:

• /opt/tomcat/webapps/manager/META-INF/
• /opt/tomcat/webapps/host-manager/META-INF/

And modify the context.xml file in both location to be exactly the same, allowing access to you local LAN as well as the localhost

<Context antiResourceLocking="false" privileged="true" >
  <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="^.*$" />
<!--
    <Valve className="org.apache.catalina.valves.RemoteAddrValve"
         allow="127\.\d+\.\d+\.\d+|192\.\d+\.\d+\.\d+|::1|0:0:0:0:0:0:0:1" />
-->
</Context>

I the above screenshot, I'm giving full access to the 192.0.0.0 subnet

Hope this guide helps! If you have enjoyed reading this article about how to install Apache Tomcat on CentOS 7 you might like this other article of mine too!

• Install Squid, webmin and sent data to Splunk with CentOS 7 https://www.nazaudy.com/install-squid-webmin-and-sent-data-to-splunk-with-centos-7

London, 11 March 2018

References

• https://www.digitalocean.com/community/tutorials/how-to-setup-additional-entropy-for-cloud-servers-using-haveged 
• https://www.vultr.com/docs/how-to-install-apache-tomcat-8-on-centos-7