Apache Tomcat is a web server and servlet container that is used to serve Java applications. Tomcat is an open source implementation of the Java Servlet and JavaServer Pages technologies, released by the Apache Software Foundation. This tutorial covers the basic installation and some configuration of the latest release of Tomcat 9 on your Ubuntu 16.04 server.
Step 1: Install Java
Tomcat requires Java to be installed on the server so that any Java web application code can be executed. We can satisfy that requirement by installing OpenJDK with apt-get.
First, update your apt-get package index:
Then install the Java Development Kit package with apt-get:
apt-get install default-jdk
Now that Java is installed, we can create a tomcat user, which will be used to run the Tomcat service.
Step 2: Create Tomcat User
For security purposes, Tomcat should be run as an unprivileged user (i.e. not root). We will create a new user and group that will run the Tomcat service.
First, create a new tomcat group:
Next, create a new tomcat user. We’ll make this user a member of the tomcat group, with a home directory of /opt/tomcat (where we will install Tomcat), and with a shell of /bin/false (so nobody can log into the account):
useradd -s /bin/false -g tomcat -d /opt/tomcat tomcat
Now that our tomcat user is set up, let’s download and install Tomcat.
Step 3: Install Tomcat
The best way to install Tomcat 9 is to download the latest binary release then configure it manually.
Find the latest version of Tomcat 9 at the Tomcat 9 Downloads page. At the time of writing, the latest version is 9.0.14, but you should use a later stable version if it is available. Under the Binary Distributions section, then under the Core list, copy the link to the “tar.gz”.
Next, change to the /tmp directory on your server. This is a good directory to download ephemeral items, like the Tomcat tarball, which we won’t need after extracting the Tomcat contents:
Use curl to download the link that you copied from the Tomcat website:
We will install Tomcat to the /opt/tomcat directory. Create the directory, then extract the archive to it with these commands:
mkdir /opt/tomcat tar xzvf apache-tomcat-9.0.14.tar.gz -C /opt/tomcat --strip-components=1
Next, we can set up the proper user permissions for our installation.
Step 4: Update Permissions
The tomcat user that we set up needs to have access to the Tomcat installation. We’ll set that up now.
Change to the directory where we unpacked the Tomcat installation:
Give the tomcat group ownership over the entire installation directory:
chgrp -R tomcat /opt/tomcat
Next, give the tomcat group read access to the conf directory and all of its contents, and execute access to the directory itself:
chmod -R g+r conf chmod g+x conf
Make the tomcat user the owner of the webapps, work, temp, and logs directories:
chown -R tomcat webapps/ work/ temp/ logs/
Now that the proper permissions are set up, we can create a systemd service file to manage the Tomcat process.
Step 5: Create a systemd Service File
We want to be able to run Tomcat as a service, so we will set up systemd service file.
Tomcat needs to know where Java is installed. This path is commonly referred to as “JAVA_HOME”. The easiest way to look up that location is by running this command:
The correct JAVA_HOME variable can be constructed by taking the output from the last column (highlighted in red) and appending /jre to the end. Given the example above, the correct JAVA_HOME for this server would be:
Your JAVA_HOME may be different.
With this piece of information, we can create the systemd service file. Open a file called tomcat.service in the /etc/systemd/system directory by typing:
Paste the following contents into your service file. Modify the value of JAVA_HOME if necessary to match the value you found on your system. You may also want to modify the memory allocation settings that are specified in CATALINA_OPTS:
[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
When you are finished, save and close the file.
Next, reload the systemd daemon so that it knows about our service file:
Start the Tomcat service by typing:
systemctl start tomcat
Double check that it started without errors by typing:
systemctl status tomcat
If you want to enable the Tomcat service, so it starts on server boot, run this command:
systemctl enable tomcat
Source: Digital Ocean