Login into the server as root user and update the Ubuntu repository.
apt-get update
Now install curl , ca-certificates, and postfix packages.
sudo apt-get install -y curl openssh-server ca-certificates sudo apt-get install -y postfix
During Postfix installation a configuration screen may appear. Select ‘Internet Site’ and press enter. Use your server’s external DNS for ‘mail name’ and press enter.
Add the GitLab package repository.
curl https://packages.gitlab.com/install/repositories/gitlab/gitlab-ee/script.deb.sh | sudo bash
Install the GitLab package. Change https://gitlab.devopsconfig.com to the URL at which you want to access your GitLab instance. GitLab will automatically request for a LetsEncrypt certificate
sudo EXTERNAL_URL="https://gitlab.devopsconfig.com" apt-get install gitlab-ee
You’ll be redirected to a password reset screen on your first visit. Enter the password for the default administrator account and you will be redirected to the login screen. The default username is “root”