Katalon - Headless Ubuntu

Install required packages:

sudo apt-get install xvfb firefox openjdk-8-jre

Edit /etc/systemd/system/xvfb.service:

[Unit]
Description=Xvfb service
[Service]
ExecStart=/usr/bin/Xvfb :1 -screen 0 1280x1024x24 -ac +extension GLX +render -noreset
[Install]
WantedBy=multi-user.target

Start now and also make sure it starts on boot:

systemctl daemon-reload
systemctl start xvfb
systemctl enable xvfb

Run it starting from ./katalon folder:

export DISPLAY=":1" && ./katalon -noSplash  -runMode=console -consoleLog -projectPath="/x/moodle_shib_login/moodle_shib_login.prj" -retry=0 -testSuitePath="Test Suites/Moodle Suite" -executionProfile="default" -browserType="Firefox (headless)" 2>/dev/null | grep '\[PASSED\]'