sudo mkdir -p /opt/tomcat

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

sudo passwd tomcat
Enter new UNIX password: 
Retype new UNIX password: 
passwd: password updated successfully

cd /opt/Download
sudo wget http://archive.apache.org/dist/tomcat/tomcat-8/v8.5.51/bin/apache-tomcat-8.5.51.zip -P /opt/Download

sudo apt install unzip
sudo unzip apache-tomcat-8.5.51.zip
sudo mv apache-tomcat-8.5.51/* /opt/tomcat
sudo chown -R tomcat:tomcat /opt/tomcat
sudo chmod +x /opt/tomcat/bin/*.sh
sudo usermod -aG sudo tomcat # adding tomcat as sudo-user

sudo vi /etc/environment 

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/lib/jvm/current/bin:/usr/lib/jvm/current/db/bin:/usr/lib/jvm/current/jre/bin:/opt/apache-maven-3.6.3/bin"
J2SDKDIR="/usr/lib/jvm/current"
J2REDIR="/usr/lib/jvm/current/jre"
JAVA_HOME="/usr/lib/jvm/current"
MAVEN_HOME=/opt/apache-maven-3.6.3
CATALINA_HOME="/opt/tomcat"

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

[Unit]
Description=Tomcat 8.5 servlet container
After=network.target

[Service]
Type=forking
User=tomcat
Group=tomcat

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

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

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

[Install]
WantedBy=multi-user.target

sudo systemctl daemon-reload
sudo systemctl start tomcat
sudo systemctl status tomcat

● tomcat.service - Tomcat 8.5 servlet container
   Loaded: loaded (/etc/systemd/system/tomcat.service; disabled; vendor preset: enabled)
   Active: active (running) since Wed 2019-11-27 21:58:03 UTC; 4s ago
  Process: 2258 ExecStart=/opt/tomcat/bin/startup.sh (code=exited, status=0/SUCCESS)
 Main PID: 2270 (java)
    Tasks: 52 (limit: 9246)
   CGroup: /system.slice/tomcat.service
           └─2270 /usr/lib/jvm/jdk1.8.0_231/bin/java -Djava.util.logging.config.file=/opt/tomcat/conf/logging.properties -Djava.util.logging.manager=org.apache.juli.ClassLoaderLog

nov. 27 21:58:03 vivo-uqam systemd[1]: Starting Tomcat 8.5 servlet container...
nov. 27 21:58:03 vivo-uqam startup.sh[2258]: Tomcat started.
nov. 27 21:58:03 vivo-uqam systemd[1]: Started Tomcat 8.5 servlet container.

# if there is no error activate tomcat for a boot on server startup
sudo systemctl enable tomcat

Created symlink /etc/systemd/system/multi-user.target.wants/tomcat.service → /etc/systemd/system/tomcat.service.

sudo ufw allow 8080/tcp

sudo reboot -f

sudo -s -u tomcat
cd /opt/tomcat

vi conf/tomcat-users.xml

<?xml version="1.0" encoding="UTF-8"?>
<tomcat-users xmlns="http://tomcat.apache.org/xml"
              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://tomcat.apache.org/xml tomcat-users.xsd"
              version="1.0">
<role rolename="manager-gui"/>
<role rolename="tomcat"/>
<user username="vivo" password="<must-be-changed>" roles="manager-gui,tomcat"/>
</tomcat-users>

vi ./webapps/manager/META-INF/context.xml

<?xml version="1.0" encoding="UTF-8"?>
    <Context antiResourceLocking="false" privileged="true" >
              <Valve className="org.apache.catalina.valves.RemoteAddrValve"
                               allow=".*"/>
</Context>

systemctl restart tomcat