Example of preparing the environment for Ubuntu Server#

Update the system:

sudo apt update
sudo apt upgrade -y

Java 17 must be installed on the server. Java installation instruction.

sudo apt install openjdk-17-jdk

Set up the firewall:

Allow the SSH connection:

sudo ufw allow ssh

Base rules:

sudo ufw default deny incoming
sudo ufw default allow outgoing

Allow HTTP and HTTPS connections:

sudo ufw allow http
sudo ufw allow https

Enable the firewall:

sudo ufw enable