salt-master from systemsmanagement:Uyuni:Stable:Ubuntu1804-Uyuni-Client-Tools project

For xUbuntu 18.04 run the following:

Keep in mind that the owner of the key may distribute updates, packages and repositories that your system will trust (more information).

echo 'deb http://download.opensuse.org/repositories/systemsmanagement:/Uyuni:/Stable:/Ubuntu1804-Uyuni-Client-Tools/xUbuntu_18.04/ /' | sudo tee /etc/apt/sources.list.d/systemsmanagement:Uyuni:Stable:Ubuntu1804-Uyuni-Client-Tools.list
curl -fsSL https://download.opensuse.org/repositories/systemsmanagement:Uyuni:Stable:Ubuntu1804-Uyuni-Client-Tools/xUbuntu_18.04/Release.key | gpg --dearmor | sudo tee /etc/apt/trusted.gpg.d/systemsmanagement_Uyuni_Stable_Ubuntu1804-Uyuni-Client-Tools.gpg > /dev/null
sudo apt update
sudo apt install salt-master