Guide to set up Apache2 and Tomcat8.5 on an Ubuntu 18.04?

Question

Does anyone know a good guide to set up Apache2 and Tomcat8.5 on an Ubuntu 18.04? (Including the Apache Tomcat Connectors: mod_jk)

Answer 1

There are lots of guides online that go over how to accomplish each of these tasks, but it seems many of them leave out one or two steps that then lead to questions on sites like this one. That said, DigitalOcean puts out some of the better walk-throughs for common software packages.

That said, AskUbuntu isn't really a site where one drops links and walks away. Link rot is a real thing and should be avoided when possible. So, with this in mind, let's install some software.

Apache2 on Ubuntu Server 18.04

This is how one would install Apache on an up-to-date Ubuntu 18.04:

0. Connect to the machine
1. Update apt:

   sudo apt update
   

2. Install Apache:

   sudo apt install apache2
   

3. Allow Apache through the firewall by first listing applications ufw is aware of:

   sudo ufw app list
   

   This will give you something like:

   Available applications:
     Apache
     Apache Full
     Apache Secure
     OpenSSH
   

   Allow Apache:

   sudo ufw allow 'Apache'
   

   Confirm the status:

   sudo ufw status
   

   You should see something similar to this:

   Status: active
   
   To                         Action      From
   --                         ------      ----
   OpenSSH                    ALLOW       Anywhere                  
   Apache                     ALLOW       Anywhere                  
   OpenSSH (v6)               ALLOW       Anywhere (v6)             
   Apache (v6)                ALLOW       Anywhere (v6)
   

4. Test the web server works in the browser by entering the server's IP address. You should see a stock Apache page with the Ubuntu logo and some configuration information.

Source: DigitalOcean

Install Tomcat 8.5

Tomcat 8.5 was the version available with Ubuntu 16.04 and Tomcat 9 was the version available for 18.04. That said, if you really must have 8.5 on your 18.04 server, this is how you can do it.

(Optional Steps — To be performed only if you have disconnected from the server after installing Apache)

0. Connect to the machine
1. Update apt

   sudo apt update
   

Now let's install Tomcat 8.5:

1. Install the Java Development Kit:

   sudo apt-get install default-jdk
   

2. Create a group and user for Tomcat to use:

   sudo groupadd tomcat
   sudo useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat
   

3. Download Tomcat 8.5 from the Apache Tomcat website. As of this writing, 8.5.65 is the most recent version. You can download this via curl:

   curl -O https://downloads.apache.org/tomcat/tomcat-8/v8.5.65/bin/apache-tomcat-8.5.65.tar.gz
   

4. Tomcat will be saved to the /opt/tomcat directory, so let's get that set up:

   sudo mkdir /opt/tomcat
   sudo tar xzvf apache-tomcat-8*tar.gz -C /opt/tomcat --strip-components=1
   

5. Now let's set the permissions correctly:

   cd /opt/tomcat
   sudo chgrp -R tomcat /opt/tomcat
   sudo chmod -R g+r conf
   sudo chmod g+x conf
   sudo chown -R tomcat webapps/ work/ temp/ logs/
   

6. Next we need to get the current location of Java:

   sudo update-java-alternatives -l
   

   You will see something like this:

   java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64
   

   The path will be needed for JAVA_HOME, which will be set in the next step.
7. Create a systemd .service file for Tomcat using an editor of your choice:

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

   Paste the following into the file:

   [Unit]
   Description=Apache Tomcat Web Application Container
   After=network.target
   
   [Service]
   Type=forking
   
   Environment=JAVA_HOME=/usr/lib/jvm/java-1.8.0-openjdk-amd64/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=/opt/tomcat/bin/shutdown.sh
   
   User=tomcat
   Group=tomcat
   UMask=0007
   RestartSec=10
   Restart=always
   
   [Install]
   WantedBy=multi-user.target
   

   Remember to change JAVA_HOME to the path from the last step, and keep /jre at the end of the path. Once done, save and close the file.
8. Reload the systemd daemon:

   sudo systemctl daemon-reload
   

9. Start Tomcat:

   sudo systemctl start tomcat
   

   Confirm it's working:

   sudo systemctl status tomcat
   

10. Allow Tomcat through the firewall:

    sudo ufw allow 8080
    

    And then test the installation with http://server_domain_or_IP:8080
11. Set Tomcat to automatically start at boot:

    sudo systemctl enable tomcat
    

12. Now to configure the management interface. Open the configuration XML file and set a decent login and password:

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

    You'll see something like this:

    <tomcat-users ...>
        <user username="crazyTown" password="superSecretPassword!123" roles="manager-gui,admin-gui"/>
    </tomcat-users>
    

    Save the file.
13. Restart Tomcat:

    sudo service tomcat restart
    

14. Test the web interface again in the browser.

Source: DigitalOcean

mod_jk for Apache

This is the final step.

(Optional Steps — To be performed only if you have disconnected from the server after installing Apache)

0. Connect to the machine

1. Update apt

   sudo apt update
   

2. Install mod_jk:

   sudo apt install libapache2-mod-jk
   

3. Enable the redirect port on Tomcat:

   sudo vi /opt/tomcat/server.xml
   

4. Uncomment the line that looks like this:

   <Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />
   

5. Create a workers.properties file for Apache:

   sudo vi /etc/apache2/workers.properties
   

6. Paste the following into the new file:

   # Define one worker using AJP13
   worker.list=worker1
   
   # Set the properties
   worker.worker1.type=ajp13
   worker.worker1.host=localhost
   worker.worker1.port=8009
   

7. Instruct Apache to use the file:

   sudo vi /etc/apache2/mods-available/jk.conf
   

   Find the JkWorkersFile property and set it to the file you just created:

   JkWorkersFile /etc/apache2/workers.properties
   

8. Finally, ensure Apache passes through to Tomcat:

   sudo vi /etc/apache2/sites-enabled/000-default.conf
   

   Then add this to your <VirtualHost *:80> configuration:

   JkMount /api worker1
   

9. Restart Tomcat and Apache:

   sudo service tomcat restart
   sudo service apache2 restart
   

Source: My endless configuration notes in Evernote ...

This should give you everything you need to get these three pieces of software working together. This was tested in a VirtualBox VM running Ubuntu Server 18.04.5 LTS.