sudo apt update

sudo apt install default-jdk

Verify Java has been installed by checking its version:

java -version

Java is now installed!

sudo apt install tomcat9 tomcat9-admin

Enable Tomcat to start at system boot:

sudo systemctl enable tomcat9

Start the service with:

sudo service tomcat9 start

Confirm the service is running with:

sudo service tomcat9 status

If the service is running ok, a line saying active will be displayed.

wget https://sourceforge.net/projects/geoserver/files/GeoServer/2.20.3/geoserver-2.20.3-war.zip

Stop Tomcat before unzipping the files:

sudo service tomcat9 stop

Move the downloaded file to the webapps directory:

sudo mv geoserver-2.20.3-war.zip /var/lib/tomcat9/webapps

Navigate to the webapps directory:

cd /var/lib/tomcat9/webapps

Unzip the file:

sudo unzip geoserver-2.20.3-war.zip

If unzip has not been installed, use:

sudo apt install unzip

After installing Tomcat, type:

sudo nano /etc/tomcat9/tomcat-users.xml

Add the following three lines to the xml file:

<role rolename=“admin-gui”/>

<role rolename=“manager-gui”/>

<user username=“tomcat” password=“pass” roles=“admin-gui,manager-gui”/>

Reboot (or simply restart tomcat service):

sudo reboot

Geoserver is accessible at: http://192.168.92.20:8080/geoserver (or whatever is your IP/domain)