install

update && upgrade

update system

sudo apt update && sudo apt upgrade 

ensure services

sudo systemctl enable --now ssh

firewall (UFW)

sudo ufw allow 22/tcp
sudo ufw allow 80/tcp
sudo ufw allow 443/tcp
sudo ufw enable

add repo (ce)

sudo apt install -y curl
curl "https://packages.gitlab.com/install/repositories/gitlab/gitlab-ce/script.deb.sh" | sudo bash

set url and install

sudo EXTERNAL_URL="https://gitlab.example.com" apt install gitlab-ce